How to Treat Parasites in Aquarium Fish

When you buy an aquarium fish, did you know that it has traveled from a fish farm to a wholesaler to a pet store before it got to you? This means that your fish could have acquired an internal or external parasite. Wild-caught fish are especially prone to carrying parasites, if not multiple types at the same time. Most aquarium fish don’t stay in the store long enough for parasitic diseases to be checked. You may need to use one of these antiparasitic medication if your fish is showing signs of parasitic disease: a swollen stomach, thin disease, hole in the head, unusual-looking, discolored stool, or swollen abdomen.

1. Ich-X

Hikari is known for producing high-quality fish food, but their Pond Solutions and Aquarium Solutions product lines also make excellent fish medicines. After testing dozens ich medicines in the United States we found Ich-X to be the most effective for treating ich, white spot disease, other external protozoan parasites, and mild fungal infections. Ich-X is actually used to prevent any fish from being sold to customers. It has two active ingredients, formaldehyde & malachite-green chloride. It is safe for scaleless fish and invertebrates as well as live plants.

If your fish appears to have a lot of white salt crystals, it may be ich. You should always keep first aid medication like Ich-X handy.

There are two types Ich-X: Aquarium Solutions IchX is for home aquariums; Pond Solutions IchX is for larger tanks that hold 50 gallons or greater. Follow these steps to get Aquarium Solutions Ich-X.

1. Clean the aquarium and do a water change. Remove any chemical filtration (like activated carbon or Purigen) and UV sterilizers. 2. One teaspoon (5 ml), Ich-X for every 10 gallons water is recommended. 3. Every 24 hours, change one-third of the tank water and repeat the dose. 4. Keep your treatment going for at least three more days after you have seen any symptoms of the disease.

Pond Solutions Ich-X is stronger than Aquarium Solutions Ich-X, so use the same directions but with a dosing concentration of 1 teaspoon (5 ml) of medicine per 50 gallons of water. For more details on how to recognize and treat ich, read our full article here.

2. ParaCleanse

Fritz ParaCleanse, another proven medication that we use to preventively treat any new fish entering our retail store is safe and can be used safely in conjunction with IchX. It is used to treat internal parasites as well as some external parasites like:

– Tapeworms (e.g., skinny or wasting disease) – Gill and skin flukes (e.g., Gyrodactylus species) – Hole-in-the-head (HITH) disease (e.g., Hexamita and Spironucleus species)

ParaCleanse contains praziquantel to take care of worms and flukes, as well as metronidazole to kill certain bacteria and protozoans. It is safe to use on scaleless fish, fish fry and shrimp as well as snails, shrimp, and aquarium plant species. Follow the manufacturer’s recommendations if your fish is suspected to have one of these parasites. Don’t give the medicine half-doses as it may not be effective.

1. Clean your aquarium and get rid all chemical filtration or UV sterilizers. 2. ParaCleanse is administered once daily for 10 gallons. 3. Dose 1 packet of ParaCleanse for every 10 gallons water on Day 3. 4. Do a 25% water exchange on Day 5 5. Wait 2 weeks before administering any other medications so that your fish have a chance to recover and gain weight. To help them pass the dead worms, feed foods with fiber and roughage, such as spirulina brine shrimp, daphnia, algae wafers, and Repashy Soilent Green. 6. After 2 weeks, repeat the 5-day treatment by following Steps 1-4. (Eggs are not affected by the medicine, so we have to wait for the new worms to hatch out. This is why it takes stores 2 weeks to get rid of all internal parasites. 7. [Optional] The majority of parasites can be eliminated by repeating the 5-day treatment once. You can make sure that your fish are healthy by waiting 2 weeks before repeating Steps 1 through 4.

Tapeworm eggs are not affected with most medications so we need to wait until new worms hatch before treating them. That is why we recommend redosing after 2 weeks once they have hatched.

ParaCleanse does not cause any harm to fish, and multiple treatments can be used. ParaCleanse can be costly so you might consider putting your fish into a smaller quarantine to reduce the amount of water required.

Should the fish be medicated with food or water? It can be difficult to manage medicated fish food. Because they are sick, sick fish will often not eat as much or as often as normal. It can also be difficult to keep track of how much medication each fish is taking. This could lead to fish consuming too many medications while others are eating too little. Meditated food may be an option if you only have one fish that is eating well. If you are treating multiple animals, we recommend medications that dissolve in the water and treat the whole tank so that we can ensure every animal gets the right concentration.

What is the treatment plan for the Quarantine Med Trio? After you have given your fish a 7-day soak with ParaCleanse and Ich-X, follow these instructions, starting at Step 5.

3. PraziPro

PraziPro has a higher concentration of praziquantel, so we recommend using it when ParaCleanse isn’t quite strong enough or if we’re seeing a problem with certain shrimp parasites like Vorticella and Scutalleria japonica.

Similar to ParaCleanse, PraziPro is safe for fish, invertebrates, plants, and beneficial bacteria, and it’s primarily used to treat tapeworms, flukes, flatworms, and turbellarians. To use PraziPro, follow these steps:

1. Clean the aquarium and remove any chemical filtration and UV sterilizers. 2. Use 1 teaspoon (5 ml), PraziPro for every 20 gallons of water. 3. Allow the medication to rest for 7 days. You can repeat the dosage as often as you need, but not more than three times per day.

Wild-caught fish often contain lots of parasites that may require three rounds of treatment to fully deworm.

In our personal tanks, we’ve use PraziPro as part of the deworming process for our puffers. ParaCleanse is first treated for five days. Then, wait two weeks. Then we do a second 5-day treatment of ParaCleanse and then wait a month. As our final deworming step, we apply the PraziPro 7 day treatment.

4. CyroPro

Pond Solutions CyroPro has been specially designed to treat external parasites such as fish lice (e.g. Argulus species) or anchor worms, (e.g. Lernaea species). The active ingredient of cyromazine works by preventing parasitic insects and crustaceans from molting their exoskeletons. This treatment is safe for fish, plants, snails, and insects. However, you might want to remove your shrimp, crab, and any other crustaceans before it can be used.

1. Perform a water change in the aquarium or pond, and get rid of any chemical filtration and ultraviolet sterilizers. 2. Shake the bottle well and dose 1 teaspoon (5 ml) of CyroPro per 50 gallons of water. 3. Change the water and repeat the treatment every 7 days for at least 21 uninterrupted days. If you miss a day of treatment, you can restart the treatment.

External parasites like fish lice (seen above) and anchor worms are visible to the naked eye and are often found on pond fish like goldfish and koi.

Each CyroPro dose is preceded by a water change. This helps to replenish dissolved oxygen, remove excess nutrients and reduce the number of water-borne parasites.

5. Expel-P

Fritz Expel-P is a fast-acting dewormer used to specifically treat parasites such as planaria, roundworms and nematodes (such as camallanus red worms), nodular worms, and hookworms. Infected fish may exhibit signs such as anemia, a swollen stomach, red worms leaking into the anus, rapid breathing, or loss of appetite.

The active ingredient is levamisole hydrochloride (HCl), which causes paralysis and death of the worms, but it will not harm your biological filtration, aquarium plants, invertebrates, or healthy fish.

Fritz ParaCleanse is a multi-treatment program that ensures all eggs are hatched. Follow the manufacturer’s instructions and recommended dosage:

1. Clean the aquarium and remove any chemical filtration and UV sterilizers. 2. For every 10 gallons water, use 1 packet Expel-P. 3. Do a 25% water change after 24 hours. Make sure to vacuum the substrate using an aquarium siphon. This will remove paralyzed and irritated worms. 4. After 1 week, repeat the treatment to get rid of any new worms that hatched out. 5. Continue the weekly treatments as needed until the worms have disappeared or the fish are regaining weight again.

Bonus: Aquarium Salt

If you do not have access to these medications, aquarium salt is useful for the treatment of external parasites (but isn’t as effective for internal parasites). The salt works by dehydrating the parasites to death before the fish (which have more mass and stored water) are affected. For complete instructions, see our full article on how to treat sick fish with salt.