5 Best Fish Tank Ideas for A 20-Gallon Aquarium


5 Best Fish Tank Ideas for a 20-Gallon Aquarium

A 20-gallon aquarium can be like a blank canvas. There are so many possibilities when it comes to choosing the decorations, live plants, and of course aquarium fish. These are five of the best setup ideas that we love to share with you.

1. The “I Just Want It to Look Good” Aquarium

If you are not an expert aquascaper, or a creative artist, it might be difficult to create an exquisite design for your aquarium. You don’t have to worry, this is a beautiful and simple setup that will amaze you every time it is displayed. The goal is to fill the back half of the aquarium with plants of all different textures and colors, such as java fern, stem plants, vallisneria, or a dwarf aquarium lily. For maximum impact, add a group of 12-20 neon tetras. There’s something instantly mesmerizing about seeing a large group of identical fish swimming in an underwater forest of plants.

Neon tetras tend to swim in the middle of the aquarium, so you can add a few bottom dwellers to round out the community, such as a red cherry shrimp colony that pops against the greenery, three to four kuhli loaches to clean up the tank at night, or a few nerite snails for algae control. You can keep your tank clean by choosing slow-growing plants and animals that aren’t likely to breed quickly. This tank is attractive to everyone because it doesn’t have a lot of different species, but instead looks like a carefully crafted piece of art. People will be inspired by its simplicity and beauty to create their own tank.

Neon tetras have bright blue and red stripes that really stand out against a wall of aquatic plants.

2. The “Fish Breeding” Aquarium

Setting up a dedicated tank for breeding fish is enjoyment for the whole family. You can teach kids about nature, get your partner more interested in aquariums, and even sell the offspring to your local fish store or other hobbyists for profit. Most people start with livebearers (or fish who bear live young) like guppies or platies, but have you ever considered breeding bristlenose (or bushynose) plecos before? Because they are easy to breed, many varieties have been created, including wild-type brown, albino and super red plecos. The male will claim his own territory by providing a pleco cave. For spawning, give the male and female plenty of healthy foods such as Repashy gel foods and frozen bloodworms. Then the male will entice the female to his cave, trap her inside to lay eggs, and faithfully fan the eggs (to increase water flow) until they hatch. You can place the parents in an aquarium that is larger than your home. After the babies hatch, move them all into your 20 gallon tank.

When the fry can swim freely, feed them plenty of Repashy gel foods, flake foods and canned green beans. You will need to change the water frequently if you want the fish to stay healthy. To decrease the buildup of nitrogen waste (and make the aquarium look better), consider adding live plants to the aquarium. Anubias and Java fern attached to driftwood provide cover and food for the babies. Once they are about 2 inches (5 cm) long, you can move a few of your favorites to other aquariums to help with algae control and sell the rest to your local fish store. Your 20-gallon aquarium will be ready for your next breeding project.

In order for breeding to occur, you need at least one male and one female. Female bristlenose plecos are more rounded than males.

3. The Rainbowfish Aquarium

Most rainbowfish are too big to fit comfortably in a 20-gallon fish tank, but it’s the perfect size for rainbowfish in the Pseudomugil genus and other dwarf rainbowfish that remain under 2-2.5 inches (5-6.3 cm) long. Some of the most popular species include the neon red (P. luminatus), forktail blue-eye or furcata (P. furcatus), spotted blue-eye (P. gertrudae), Celebes (Marosatherina ladigesi), and threadfin rainbowfish (Iriatherina werneri). The males are brighter and can “dance” when they are around females. So make sure you have both genders in your aquarium.

As surface-dwelling fish, rainbowfish inhabit the top one-third of aquariums, so make sure to have a tight-fitting tank lid that prevents them from jumping out. You can add lots of floating plants and mosses to encourage them to lay eggs daily, although you may not see any fry until you take out the eggs. Because of their small mouths, feed them tiny floating or slowly sinking foods, such as baby brine shrimp, daphnia, cyclops, crushed flakes, micro pellets, and Easy Fry and Small Fish Food.

Dwarf rainbowfish can be a tad more expensive at $10 to $15 each, and ideally you want a school of six or more. To fill out the rest of the tank, you can get other community fish like small tetras and rasboras that swim in the middle and corydoras and snails that scavenge at the bottom. (Cherry shrimp may get picked on since rainbowfish are active creatures that love to eat.)

While dwarf rainbowfish can be a little harder to source, keep searching because their gorgeous colors and lively behavior are worth the hunt.

4. The Oddball Aquarium

Most people think of oddballs as rare or interesting fish, but what about keeping an oddball invertebrate? Filter-feeding shrimp such as the bamboo or wood shrimps (Atyopsis Moluccensis), and vampire shrimps (Atya gabonensis), are equipped with large, feathery mitts that can catch and eat small particles suspended in the water. Because of the way they feed, don’t set up a powerful hang-on-back (HOB) or canister filter that polishes all the little crumbs from the water. You can use a sponge filter, or an airstone with plenty of plants to help them climb on. You can then give them powdered foods such as Repashy gel food, Hikari First Bite and other specialty foods that are suitable for filter-feeding shrimp. You should notice food particles in the aquarium’s water when you add the powder.

For a 20-gallon fish tank, you can get one to two bamboo shrimp and one vampire shrimp. The shrimp grow rather large, ranging from 3-6 inches (8-15 cm) each, so you want them to stand out as the centerpieces of the aquarium by pairing them with nano fish like celestial pearl danios, Norman’s lampeye killifish, and chili rasboras. Also, consider adding some snails, amano shrimp, or cherry shrimp to clean up the food particles that fall to the substrate. This invertebrate-centric tank is a great option if you’re looking for a unique community tank that will be noticed by everyone.

If your filter-feeding shrimp are scavenging on ground, then they probably don’t get enough food. Increase their daily portion.

5. The Unheated Aquatic Aquarium

Looking for fish that can live in a 20-gallon tank with no heater? If your room temperature is 62degF (17degC) and above, then this danio aquarium may be the perfect choice. Danios are a highly active, torpedo-shaped fish that come in many varieties and colors, such as zebra, leopard, long fin, and even Glofish. To create a rainbow of colors, get 12-15 of them.

Danios swim at all layers of the aquarium, but you can add some other species that like cooler waters, such as five or six salt and pepper corydoras to pick up any food that gets past the danios. Amano shrimps, Japanese trapdoor snails, nerite and Malaysian trumpet snails are all cool-temperature invertebrates which would make good tank mates. Keep your snails well-nourished with calcium-based foods and enough minerals in their water. If you want an action-packed, beginner-friendly tank full of hardy fish, you can’t go wrong with an aquarium of danios.

Long-fin zebra danios have a high energy, beautiful design, and are affordable.