Coral reef trade and you

By Hannah Scutter BSc

Marine aquariums are becoming increasingly more popular amongst amateur enthusiast who want to bring a small piece of paradise into urban living rooms. Items such as corals, live rock, marine fish and invertebrates are all appearing in our pet shops. Naturally occurring wild corals can be found off the coast of Indonesia, Australia and the Philippines and as well as being home to many fish and invertebrates they also play a vital role in local populations through a range of ecosystem services. Such coral reefs can provide a large market in the food industry with 15 tonnes of fish and sea food harvested per hectare per year [1]. Specimens can be sold as souvenirs and be part of a large attraction for tourists bringing income to nearby coastal communities. Corals are also a natural storm defence by acting as a wave dispersion system and have been used in the medical industry as a treatment for cancer and Alzheimer’s disease [2]. Together the value of such services is unknown but the exportation of live corals for the use in ornamental domestic tanks was estimated to be over $200 million USD in 2000 [3]. Of these varied species the harder corals are favoured. However, these are the slower growing of the taxa and are therefore sparse in supply. Because of this they have been declared as vulnerable to exploitation by CITIES since 1990 [4]. If such species were to be eradicated then smaller faster growing corals would thrive and bring with them ‘pest’ species and algae disturbances [4]. This potentially changing our aquatic ecosystems forever. A fifth of coral has already been lost due to climate change and exploitation and an estimated further 15% will be lost over the next decade unless we the consumer try to change things.

From the sea bed to your tank

Following a coral collector around the Islands off Fiji, 200 pieces of coral can be collected per day, six days a week [5]. Once collected the specimens are taken by boat to a holding station in land where they are kept in fresh seawater tanks. Despite the lack of filtration systems there is a less than 2% mortality rate of those collected, although colours have been seen to deteriorate. Shipments are made twice a week to the US and Europe where tanks are emptied and refilled ready for the next incoming batch [5]. Once the specimens have reached the wholesaler in the receiving country they are held similarly to the holding stations off Fiji but with many filters and protein skimmers and are then quarantined for sale purposes.

Collection and exportation of corals from the Philippines, Florida, Bali, Guam Samoa, Puerto Rico and Hawaii have since been banned, with many sites of imports to follow [4]. Currently many corals bought today have been collected from Indo pacific countries and Australia. Where corals were once bought for $1-5 USD each (1985) can now be found selling for $180 USD plus [4]. A kilogram of coral can be anywhere between $500 and $1800 USD [6]. Despite this increase the tourism industry that the Great Barrier Reef attracts is far greater than the profit of such coral trade and therefore is forcing diving collectors to target smaller unknown ‘pockets’ of corals further out to sea. Smaller ‘pockets’ of corals are at higher risk of extinction as there are likely to be self-seeding groups of corals and once they are taken they cannot be replaced [4]. In the Philippines a depth restriction for collection has meant that those corals at deeper depths can act as reproducing reservoirs that will then feed the shallower clusters being disturbed [4]. Unfortunately Australia’s depth restriction has relaxed over the years impacting this cycle.

The future is coral farming

Aquaculture is the way forward. Similar to fish, coral species can be farmed in a controlled environment and therefore reduce the pressures on the demand for wild caught specimens and therefore reducing the impact on natural coral ecosystems. Commercial aquaculture facilities currently thrive in countries such as Florida, Thailand, Malaysia and Japan [7]. European farms have more recently been developed situated closer to the consumers in Spain, Czech Republic, Belgium and Holland, thus reducing transport costs and making them more freely available [7].
As a consumer there are ways you can reduce the risk of buying wild caught specimens by always asking the owner where the specimen you are interested in originated from. Whatever the reply you can always ask further details regarding their handling and transportation. Researching websites and magazines can sometimes provide additional information and insights into their rarity and therefore the likely hood of their origin. The cost of individual species will also be an indicator as rarer wild caught items will be significantly more expensive than the more common farmed ones.


[1] UNEP, United Nations Evironmental Programme, Coral Reefs [online].…/ta…/129794/language/en-US/Default.aspx (Accessed 31 March 2016).
[2] NOAA, (2014) National Oceanic and Atmospheric Administration. [online]. (Accessed 31 March 2016)
[3]Bruckner, A. W. (2000) New Threat to Coral Reefs: Trade in Coral Organisms Issues in Science and Technology, 17, (1) pp63-8.
[4] Jones, A. M. (2011) Raiding the Coral Nurseries? Diversity, 3, pp466-482.
[5] Paletta, M. (2005) Advanced Aquarist. [online]. (Accessed 07 March 2016).
[6] Cato, J. C., Brown, C. L. (2003) Marine Ornamental Species; Collection, Culture and Conservation. Iowa: A Blackwell Publishing Company.
[7] Livengood E. J., Chapman F. A. (2007) The Ornamental Fish Trade: An Introduction with Perspectives for Responsible Aquarium Fish ownership. University of Florida IFAS Extension.

Teaching an old fish new tricks

By Hannah Scutter BSc

When training aquatic animals many people will think of dolphins and orcas, but rarely small aquarium fish. However, there are a few well known aquarium species that have been seen to learn to do just that. Species such as cichlids, in particular Oscars (Astronotus ocellatus), betta fish and even gold fish have been taught tricks by their owners. With a combination of operant conditioning, positive reinforcement, lasers and clickers these training triumphs have been achieved. Supported by videos on Youtube, various blogs and facebook pages tricks such as swimming through hoops and playing fetch have been catalogued. In one such case a small aluminium foil ball was placed into an aquarium and a fish was shown to move the ball in front of its filtration pump in order for it to be then catapulted around its tank. This ball was then chased, caught and taken back to the filtration pump for round two. Colour recognition has also been expressed through similar learning styles.

A growing interest in such fishy fun has meant that there are now courses and kits available online to help others in their training adventures.

Perhaps we should all give our fish the chance to interact with us more often.


Things to consider if you ‘Find Dory’

By Kate Redman

With the release of Finding Dory, there is sure to be an increase in people looking to purchase ‘Dory’ fish, just as there was for clownfish after Finding Nemo [1]. But how suitable are these fish for aquarium displays, and what are the things you need to consider before buying one of them? Here we take a look at both Dory and her friend Nemo, seeing as they are quite often exhibited together.

‘Nemos’ are Clownfish. Clownfish belong to the subfamily Amphiprioninae, in the family Pomacentridae [2]. The subfamily is further divided into two genera, the Premnas (which contains one species commonly known as the spine-cheeked anemonefish, or the maroon clownfish [3]) and the Amphiprion (which contains a further 29 species [2]). These different species of clownfish come in a range of yellows, oranges, red, and blacks, often in combination with white bars or patches, and can range in size from around 10cms to 18cms.

The famous Nemo is an Amphiprion, more specifically an Amphiprion ocellaris, or Ocellaris clownfish (also known as a false percula clownfish, or common clownfish) [4]. These little fish are instantly recognisable thanks to their bright orange and white banding, outlined in black, and can grow to about 11cms in length, with the females being slightly larger than the males. They are found in the Eastern Indian Ocean and the western Pacific Ocean, as well as waters off Northern Australia, Southeast Asia and Japan. Their preferred habitats are reefs and shallow, sheltered lagoons.

Of course, they are best known for where they like to call home, which also gives Amphiprioninae their other common name: anemonefish. Ocellaris clownfish inhabit three different species of anemones: Heteractis magnifica, Stichodactyla gigantea and Stichodactyla mertensii [4]. Theirs is a mutual symbiotic relationship. Clownfish are territorial, and so this little fish will protect its home anemone from other, anemone-eating, fish. In turn, the stinging tentacles of the anemone protect the clownfish from its predators, allowing it to live and breed in relative safety [5]. Further, it’s believed that the presence of a clownfish in the anemone boosts its health because the fanning behaviour of the fish aids in the removal of parasites [4]. To protect itself from the anemone’s stinging tentacles, clownfish produce a special mucus.

Reproduction and gender is an interesting situation with Ocellaris clownfish. The most mundane thing about their reproduction is they are monogamous. During spawning, males will become more aggressive and territorial towards their anemone, as well as chase and bite females in a bid to attract them [4]. Males will prepare a nest by an anemone, to be protected by its stinging tentacles, then chase a willing female to the nest to spawn and fertilise the eggs. The males will then be responsible for guarding the eggs, as well as keeping them clean, and fanning them to keep them well oxygenated. It’s after the eggs hatch that things become interesting. All baby clownfish are born gender neutral [6] into a social group. The most dominant fish is a female, the next dominant is a male and her breeding partner. Those ranked between them and the newborn are either other gender-neutral juveniles, or non-mating males (who, like the dominant male, will have gone through a gender change from being gender-neutral to male). If the female should die, then the dominant male will change sex, to become the new dominant female, and one of the more dominant non-breeding males will step up to become the new breeding male. Finding Nemo would have had a very different story line if it had adhered closer to clownfish biology!

Dory fish are better known as blue tangs, and are easily recognised by their royal-blue body, yellow tail and black markings. Like clownfish, they belong to the order Perciformes [7], but are separated from clownfish into the family Acanthuridae, of which there is only one genus: Paracanthurus. Dory is the only member of that genus; Paracanthurus hepatus. Blue Tangs are also reef fish, and share much of their range with clownfish, being present in Indo-Pacific waters from East Africa, across to the Great Barrier Reef, and up to Japan.

Blue tang reproduction is somewhat more mundane than a clownfish’s. Males aggressively court the females, and spawning and fertilising takes place at the ocean’s surface, after which the eggs are left to fend for themselves in the water [7].

As blue tangs and clownfish come from similar ocean regions and habitats, a reef aquarium set up for one, should be adequate for the other. If you are intending to house the two species together, you will be looking at the following water quality ranges for a fish only system [8,9,10,11,12,13]:

Temperature: 25-27oC
Salinity: 1.020 – 1.024 (specific gravity) or 35ppt
pH: 8.1 – 8.4
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: Phosphate: Carbonate Hardness (dKH) : 8 – 12°

However, if keeping anemones and other invertebrates, the following should be measured in addition [12; Chris Sturdy, personal communication, August 1st, 2016]:

Calcium: 400-450 ppm
Magnesium: 1250 – 1350 ppm
Iodine: 0.06 – 0.10 ppm
Strontium: 8 – 14 ppm

Lighting is another important factor that needs to be taken into account. If the tank is just housing tangs, then a number of different lighting options are available to maximise the display of the animals [14]. For instance, colour-enhancing bulbs emit light from the “warmer” end of the colour spectrum, and are used to augment or enrich colour, allowing you to display the striking blue colours of your tangs to their fullest. However, a good reef tank should also contain other living (non-fish) organisms, such as coral, seaweed (though as it’s difficult to maintain in a home aquarium, this is usually reserved for large, professional aquaria), and in the case of clownfish; anemones. In which case, your lighting requirements will become more specific to allow these organisms to flourish. Seaweeds photosynthesise, and although corals and anemones aren’t photosynthetic organisms like seaweed, they do obtain essentials nutrients from symbiotic photosynthetic algae (zooxanthellae) growing in their tissues. Therefore, if you are housing clownfish with anemones, or simply including anemones and coral for show, you will need to equip your tank with a full-spectrum light [15], or perhaps a 50/50, or an actinic white bulb, which are blended lights that encourage photosynthetic coral growth [14]. Additionally, anemones and corals need good water circulation to allow them to be able to absorb oxygen from the water, as well as to gather their food [15,16]. As such, most anemone species do well in tanks with low to moderate flow [15].

Whether installing corals, anemones, or (in the case of a large set up) algae, all good aquariums should have as their base “live rock”. The term is a bit of a misnomer, because the rock is traditionally neither a rock, nor is itself alive. Rather, it lumps of calcified skeletons of long dead corals, or other calcareous organisms (which form the majority of coral reefs) which have been collected from the ocean [17], although sustainable methods of curing rock from reefs has been developed [37]. These rocks are often encrusted with coralline algae, and hold within them a host of micro and macroscopic marine life. Live rock is important to have in an aquarium, as it aids in maintaining microbial cycles, and helps keep nutrient levels down. In essence, it is a biological filter (though should not solely replace a mechanical filtration set-up).

On top of these specifics, extra considerations need to be taken into account as each species has special requirements in order for them to survive happily in their new home.

Blue tangs can grow to be nearly three times the size of a clownfish, and are very active swimmers [8], so any reef tank will need to be of a size to comfortably house a Dory. Therefore, you will need a tank of at least 75 gallons (approx 285 litres). Moreover, blue tangs don’t always get along, so if you want to house more than one Dory, you’ll need to get an even bigger tank (100 gallons/380 litres or more). The same goes if you want to add some clownfish as, unlike the film, they may not automatically become friends. If you’re just looking to keep clownfish, you will need a tank of at least 30 gallons [9].

It is also important that you don’t simply dump the tang (or indeed any fish) into its new aquarium before the tank has completed its aquarium nitrogen cycle [8]. Doing so, before the tank contains nitrifying bacteria to break ammonia waste into less-harmful nitrogen compounds, will result in “new tank syndrome”, a situation whereby ammonia levels have reached highly stressful, or toxic, levels [18]. A likely death sentence for your newly purchased fish! Often, the suggested method of cycling is to introduce a couple of fish, maybe a hardier species, as a way of slowly introducing ammonia to the tank, thereby allowing the necessary bacteria to flourish. This can be considered cruel, as you are putting a fish (no matter how hardy) under unnecessary stress. A more humane thing to do is carry out a fishless cycling, by adding a non-live fish source of ammonia [19]. The cycle can also be sped up by adding sources of nitrifying bacteria [19]. Your tank is fully cycled once nitrates are being produced, and ammonia and nitrite levels are zero [18].

It is essential that you make sure your tank has been set up and cycled in advance of bringing your new fish home. You’ll want to introduce your fish as soon as possible to its tank, as too long in their purchased bag/container will expose them to ammonia waste build-up. Once the tank is ready, and water ranges are within acceptable parameters (in the case of tangs, especially pH, as they are particularly sensitive to variabilities in pH [20]) your fish will need to be acclimatised slowly [8], thereby allowing it to adjust to the water conditions it will ultimately be placed into. There are several methods of introducing a fish to its new tank water, namely the Floating Bag Method, the Bucket Method, and the Drip Method [21]. None of these procedures should be rushed. Doing so could put your fish under excess stress, and could introduce unwanted pathogens to your new tank. However, once acclimatised, and placed in its new home, blue tangs are pretty hardy fish.

In terms of diets, both blue tangs and clownfish are omnivorous, and feed on both algae and plankton [7,8]. Regarding dietary requirements, it is the tang that needs the most consideration when setting up a tank. Although omnivorous, they are primarily grazers [8], and will require algae-covered live rock on which to feed. In the long term, they’ll need a varied diet that includes vitamin enriched flake foods, marine seaweed (available as dried sheets similar to that used for sushi rolls), as well as frozen and live foods, all of which should help keep their colouration bright. Of these, marine seaweed is especially important for tangs. A lack of vitamin C (and possibly vitamin B complex) is believed to be a cause of a condition known as Marine Head and Lateral Line Erosion (MHLLE), something that tangs seem to be particularly susceptible to [22]. Though rarely fatal, the disease can leave disfiguring scars on a tang. MHLLE usually begins with the development of small pits around the eye, head, and adjacent area. As the ailment progresses, the holes expand and connect, to become larger lesions, eventually extending back along the fish’s lateral line. In more advanced cases, the fins and gill covering will also often erode. Food wise, clownfish are a little simpler, and will do well on flaked foods and, like the tangs, some frozen and live foods [9].

The main special requirement for clownfish is, of course, anemones. To provide a suitable and secure habitat for these little fish, the presence of anemones is a must, however, not all anemones do well in captivity [23]. As stated earlier, Ocellaris clownfish inhabit three species of anemones: Heteractis magnifica, Stichodactyla gigantea and Stichodactyla mertensii, and these organisms also have specialized requirements. Stichodactyla gigantea is from shallow water [24] and needs direct sunlight, and all three are capable of crawling around the tank, which could lead to them injuring themselves. Additionally, they need direct feeding in large quantities [23]. Even capable aquarists, who can meet the needs of these anemones, are not able to keep them alive for long, with only 1 out of 32 anemones surviving for more than five years [23]. If they do survive, they can get very big [24,25,26]. In general, reef aquariums tend to use the smaller Entacmaea quadricolor as a replacement host [4]. Failing that, clownfish may adopt a coral species as surrogate hosts, such as Euphyllia divisa, or xenia coral [4].

As you can see, what may at first seem like a simple idea of getting a Dory and a Nemo, is in fact an expensive and extensive undertaking, especially if you’re just a hobbyist getting a couple of fish for the kids. To keep these animals, you will need to provide them with a large tank, proper lighting, good filtration, and adequate water circulation, not to mention corals and anemones, which even the most expert aquarists struggle to keep. All this for an animal that may only live for about five years [8,9]. Beyond these practical issues are also the environmental issues created by the desire for these fish.

Knowing where your fish has been sourced from is important. The vast majority of ornamental marine specimens continue to be collected from the wild [27]. The clownfish, for example, is a species that makes up 43% of the global marine ornamental trade, yet only 25% of all fish making up the global trade are captive bred [2]. This means a lot of Nemos are still being taken from their reef habitats. In the past, unregulated harvesting of tropical fish has led to the decline of many species, such as the local declines of anemonefish in Kenya [28, summarised in 27]. Blue tangs are another species regularly imported into the EU, but currently in far fewer numbers than the clownfish (4 times less [29]), however, this could all change now Finding Dory has been released.

Additionally, the mode of capture of these fish can greatly affect the local habitat. Cyanide fishing was, and in some places of South East Asia still is, a common method of collecting tropical fish. A report by the National Oceanic and Atmospheric Administration puts 70-80% of US tropical fish as coming from Indonesia and the Philippines, where cyanide use is the most prevalent [30]. Cyanide is used to temporarily asphyxiate, and hence stun, fish, but its presence in the water column means it will eventually come into contact with the local corals. High doses of cyanide can cause corals to die, and medium doses cause coral to lose their symbiotic algae, leading to ‘bleaching’ events [31].

Using cyanide is also an unreliable method for collecting the fish themselves. The toxin not only can kill non-targeted species in the vicinity, but often kills the targeted animals too [32]. Further, even though a fish may be brought up alive, the use of cyanide in its capture can lead to its death shortly after (as well as cause ill effects for several weeks after) [33]. The ill effects of cyanide poisoning is further exacerbated if the animal is stressed, which is highly likely if it has just been gassed and captured.

Overall, not all the fish make it to trade, those that do could likely end up dying after purchase, and the ecosystem at the point of capture can often be irreversibly changed because of the removal of large numbers of different fish species, along with the death of corals. With the added pressure of the ‘see it want it’ desire caused by films like Finding Nemo and Finding Dory, future aquarists could unwittingly worsen the situation at these reefs.

The alternatives are fish bred through ornamental fish farms, or fish collected sustainably out of their natural habitat. Sustainable capture involves catching wild fish for aquariums by hand, using a minimum of equipment [34]. Depending on the species, collection can involve using small hand-held nets, baited traps, or the shake-down of natural objects in which fish could be hiding. This kind of capture lets fishermen carefully select how and what they catch, allowing them to target the species of interest for which they have orders. As such, this causes a minimum of damage to the habitats where the fish live, and to the fish themselves, ensuring the habitats remain viable, and that the captured fish remain healthy. This is doubly important, as sustainable capture is often a source of valuable income for poorer communities.

If you are determined to bring Nemo and Dory into your home or display, what can be done to mitigate the environmental impact of sourcing these animals? The most important thing you can do is make sure your animals come from a reputable breeder or collector. Clownfish breed well in captivity, and even a pair in a good home tank set-up could end up producing eggs [33]. With this in mind, choosing captive-reared clownfish is the way to go, and easily done. Unfortunately, blue tangs are the polar opposite, and only recently has a shoal been successfully bred in captivity [35]. However, it’s early days yet in the captive breeding of tangs, and as such, any tangs currently found in shops will be wild-caught. Because of this, you will need to do your homework to ensure your future Dory was responsibly harvested. Reputable UK companies have been working for decades to make sure cyanide-caught fish do not enter the market by working closely with their suppliers, and with local charities [34]. Additionally, as well as ensuring your fish come from good stockists, the same should be true of any live rock, corals, or anemones you use in your tanks.

It’s also worth bearing in mind that both clownfish and blue tangs are susceptible to various saltwater fish diseases and parasites [36], especially if wild caught [33]. Yet another good reason to source your animals, if possible, from captive breeders.

The reefs of Nemo and Dory may be far away, out of sight and out of mind, but our actions as aquarists, whether we be public exhibitors, or home-based hobbyists, can have big and negative impacts on their habitats. Therefore, it’s crucial we exercise an important weapon, that of choice. It is up to us to choose whether we buy a captive-bred fish, or a wild caught; whether we choose a reputable trader, or no; and whether that wild-caught animal is worth it, considering the possible damage that may have been left in its wake. With Finding Dory being released in cinemas, and the likely rush on the buying of blue tangs, such decisions are more important than ever. We don’t want the next film to have to be called No More Dory!

[1] Clown fish are serious work ( Accessed 28-May-2016

[2] Amphiprioninae ( Accessed 28-May-2016

[3] Maroon clownfish ( Accessed 28-May-2016

[4] Ocellaris clownfish ( Accessed 28-May-2016

[5] Symbiosis ( Accessed 28-May-2016

[6] Ocellaris Clownfish – Male or Female ( Accessed 28-May-2016

[7] Paracanthurus ( Accessed 28-May-2016

[8] Blue Tang ( Accessed 29-May-2016

[9] Clownfish Care ( Accessed 29-May-2016

[10] Ammonia And Nitrite ( Accessed 10-Aug-2016

[11] Keeping Up with Nitrate ( Accessed 10-Aug-2016

[12] REEFKEEPERS FAQ: Water, Filtration, Lights, Cost (1/3) ( Accessed 10-Aug-2016

[13] Ocellaris Clownfish, Captive-Bred ORA® ( Accessed 29-May-2016

[14] Choosing the Proper Lighting for Your Aquarium ( Accessed 29-May-2016

[15] Guide for Keeping Anemones in a Reef Tank ( Accessed 29-May-2016

[16] Feature Article: Water Flow is More Important for Corals Than Light, Part V ( Accessed 29-May-2016

[17] Live rock ( Accessed 08-August-2016

[18] Beginner FAQ: The Nitrogen Cycle, and “New Tank Syndrome” ( Accessed 11-August-2016

[19] Cycling an Aquarium ( Accessed 11-August-2016

[20] Pacific Blue Tang ( Accessed 15-August-2016

[21] All You Need to Know About Acclimation ( Accessed 12-August-2016

[22] What is a lateral line in fish? The functions and diseases of the lateral line ( Accessed 12-August-2016

[23] Please use Captive Raised Clown Fish Hosts ( Accessed 29-May-2016

[24] Stichodactyla gigantea ( Accessed 29-May-2016

[25] Stichodactyla mertensii ( Accessed 29-May-2016

[26] Heteractis magnifica ( Accessed 29-May-2016

[27] Friedlander A.M. (2001). Essential fish habitat and the effective design of marine reserves: Application for marine ornamental fishes. Aquarium Science and Conservation, 3(1), 135-150 (

[28] Lubbock H.R., & Polunin N.V.C. (1975). Conservation and the tropical marine aquarium trade. Environmental Conservation, 2, 229–232

[29] Taylor, M., Green, E., & Razak, T. (2003). From ocean to aquarium: A global trade in marine ornamental species. UNEP world conservation and monitoring centre (WCMC), 1–64 (

[30] Proceedings of the International Cyanide Detection Testing Workshop (

[31] Jones R.J. & A.L. Steven (1997). Effects of cyanide on corals in relation to cyanide fishing on reefs. Mar. Freshwater Res., 48, 517–22 (

[32] Hanawa M., Harris L., Graham M., Farrell A.P., & Bendell-Young L.I. (1998). Effects of cyanide exposure on Dascyllus aruanus, a tropical marine fish species: Lethality, anaesthesia and physiological effects. Aquarium Science and Conservation, 2(1), 21-34 (

[33] Clownfish Breeding ( Accessed 02-June-2016

[34] Ornamental Aquatic Trade Association 2016 Report – Wild caught ornamental fish: The trade, the benefits, the facts (

[35] UF researchers solve riddle to finding Dory: captive breeding ( Accessed 22-July-2016

[36] Saltwater Fish Disease Symptoms and Treatment (

[37] Real Reef Solutions ( Accessed 13 July 2016.

Considering the GloFish

By Stefania Unips

The GloFish is a trademarked transgenic (genetically modified) fluorescent fish. This article leaves aside the ethics of GM technologies and looks into all relevant elements regarding fish well-being irrespective of the fishes’ nature.

The first GloFish were zebra danios (Danio rerio) and later on black widow tetras (Gymnocorymbus ternetzi) and tiger barbs (Puntius tetrazona) were added to the collection. Originally developed to help detect water contaminants by becoming fluorescent in the presence of a pollutant [7], GloFish were first sold as pets in the US in 2003 [10]. They are neither dyed, nor injected, but have been added a naturally occurring fluorescent gene that they pass to their offspring. While the red variety contains a gene that is found in sea anemones, the green GloFish have the jelly fish to thank for their vibrant colour [1]. Even though GloFish sold exceptionally well [1], controversy over this scientifically engineered pet prompted the American Food and Drug Association (FDA) to issue a statement which concluded that the fish do not pose a direct threat to the food supply on the basis that tropical aquarium fish are not used for food purposes [2]. Other independent agencies, such as the Florida Division of Aquaculture [3], as well as a number of studies, have also declared GloFish safe for the environment. Concerns that GloFish could become invasive or have an edge over wild-types when it comes to attracting a mate have been dismissed. According to Alan Blake, the CEO of Yorktown Technologies, the company that produces these genetically modified organisms, GloFish are less ecologically fit than wild-types [6]. Bill Muir, who is a professor of genetics at Purdue University, has reviewed the data provided by Alan Blake [4]. He is not tied to the “product” and worked for free to conclude that “one would expect natural selection to eliminate the trans gene regardless of where it escaped or was released.” Moreover, if the fish ever did find freedom in freshwaters, their glow would make them vulnerable to predators [5].

Alan Blake insists that Yorktown Technologies is committed to humane breeding practices. The fluorescent fish used in research did not exhibit any signs of stress and their life-expectancy is unchanged. He also argues that the presence of GloFish on the market has reduced the sales of dyed and injected fish and that after 12 years of GloFish business the initial safety assessments have been confirmed [6]. The company donates money to support organizations engaged in providing clean water to poor regions in Africa, initiative that serves 20 000 people, and offers free, educational materials that teach children and teenagers about basic fish keeping practices, genetics and biology.

Yorktown Technologies is fairly honest about the manufacturing process of its novelty product and provides proper information about GloFish care. Customers are advised to consult with local fish store experts before starting a new aquarium or adding fish to a community tank and the company recommends that the fish be treated with the utmost care [7].

So where is the problem? The manufacturer’s efforts are genuine and have most certainly changed human and fish lives, but obvious positive results should not cover up potential mistakes. For example, despite advertising some suitable equipment such as air pumps and filters (which according to some customer reports cause death by suction), the company also sells plastic plants with sharp edges that may harm the fish and flashy gravel and ornaments that create an artificial environment. If GloFish are “exactly the same in terms of care, including everything from general care and temperature preferences to water quality and nutritional needs” [7] as their less radiant counterparts shouldn’t they be kept in a tank that replicates their natural habitats? These vary from flowing streams with rocky substrates to mature rice paddies and it appears that the fish thrive in a heavily planted setup [8]. Moreover, if the “one inch of fish per gallon” (1 gallon = 4.546 litres) rule of thumb applies, one 2-inch adult GloFish would need roughly 9 litres of water. If we take into account that Danios, Tetras and Barbs are sociable fish that should be kept in groups of about 6-8 individuals [9] and that the fish do reproduce if certain conditions are met, how appropriate are 8 litres or even 23 litres aquarium kits? Fry could be given away to make room for the existing tank occupiers, however “intentional breeding and/or any sale, barter, or trade, of any offspring of GloFish fluorescent ornamental fish is strictly prohibited”, according to the GloFish license notice [7].

Yorktown Technologies pays a lot of attention to the way it promotes its’ invention. Beginner aquarist and children are encouraged to “Experience the Glo” through videos, comics and even a GloFish app and on October 1st 2014 two new kinds of GloFish, Starfire Red and Cosmic Blue Tetras saw the light of day. It is unclear if GloFish are treated as living organisms with specific needs or rather as classic products whose retail success depends on the producer’s marketing strategies. “They’ve got great colour. People are tired of seeing the same thing in the pet store all the time. It’s adding a bit of excitement to the industry” declared a GloFish trader to the BBC [1]. One blogger adds that GloFish have the potential to replace marine species that are much more difficult to care for. Aquarists could benefit from the bright colours that are normally exhibited by saltwater fish with reduced effort in terms of tank and equipment requirements [10].

There are over 180 species of fluorescent fish in nature [11]. The fluorescent gene is used to study skin and prostate cancer [12], [13] and GloFish serve a valid research and educational purpose. At present, GloFish are banned from Europe, Canada and Australia [7], but in the US it appears that these fish are sold as pets with the most obvious purpose of adding novelty to the hobby. Even though in theory they should be able to live normal, fishy lives, in practice, the tank is leaking.


[1] (accessed 10th April 2016)

[2] (accessed 10th April 2016)

[3] (accessed 10th April 2016)

[4] (accessed 10th April 2016)

[5] (accessed 10th April 2016)

[6] (accessed 10th April 2016)

[7] (accessed 10th April 2016)

[8] (accessed 10th April 2016)

[9] (accessed 10th April 2016)

[10] (accessed 10th April 2016)

[11] (accessed 10th April 2016)

[12] (accessed 10th April 2016)

[13] (accessed 10th April 2016)

The Finding Nemo effect

By Stefania Unips

Oscar for Best Animated Feature in 2003, Pixar’s Finding Nemo tells the story of Marlin, a shy clownfish who sets out to find his abducted son, Nemo, with the help of a forgetful regal tang named Dory. While Marlin and his friend are facing the perils of the great ocean, Nemo is trapped in a small tank at a dentist’s office in Sydney together with a veteran group of fish.

Fining Nemo is a funny, heart-warming, visually stunning film which earned universal acclaim. But what impact did it have on the aquarium fish industry and, most importantly, on captive and wild clownfish populations?

The main idea of the movie is that fish are better off left in their natural habitats . Even though the message was clear to some audiences, two opposing phenomena occurred after the film’s release.

  • The ‘Let’s flush Nemo’ tragedy

Gill, a Moorish Idol and leader of the Tank Gang believed that ‘all drains lead to the ocean.’ This one line caused hundreds of children to flush their clownfish down the toilet in the hope of setting them free [1]. Unfortunately the kids didn’t know that fish cannot survive this journey: swirling water causes trauma; bacteria, gas and chemicals in the sewage system can poison or asphyxiate the fish and water treatment facilities always remove any solids present in the mix [2]. Despite the movie’s good intentions, it somehow managed to misinform the public, with disastrous consequences for the clownfish.

  • The ‘I want Nemo’ consequence

Studies have revealed that demand for clownfish soared after the release of the movie, as many children wanted a Nemo of their own. Because hatcheries were not able to meet the increased demand, retailers had to resort to buying wild caught specimens [3]. As a consequence, wild populations of clownfish were significantly reduced: “The lovable tropical species, immortalized in the smash Pixar movie Finding Nemo, is facing extinction  in many parts of the world because of soaring demand from the pet trade,” declared Dr. Sinclair, a researcher specialized in marine biology [4]. It may be argued that clownfish will not face extinction, however population decline is a possibility. This paper looks at the extinction risks associated with the film [5].

Why was the movie’s message so misunderstood by some and why was it completely ignored by others? Are charismatic species prone to extinction because they are charismatic?

Will Finding Dory have similar effects on Royal Blue Tangs? We will find out after the 17th of June, 2016, the official release date for the Finding Nemo sequel.







Welcome to the Aquarium Welfare Association’s blog site where the team will share their thoughts and insights into the world of aquarium welfare.

The posts here will consist of a mixture of opinion and fact. Discussion is welcome and encouraged, but it should be relevant to the subject.

You can return to the main site here,

We look forward to sharing our ideas with you.

The AWA Team