What fish do well in 5 gallons?

A 5 gallon aquarium may seem small, but it can be home to a surprising variety of fish. The key is choosing fish with small adult sizes that can thrive in a nano tank environment. Some good options for 5 gallon aquariums include betta fish, guppies, neon tetras, pygmy corydoras, and chili rasboras. With the right tank setup and compatible tank mates, these petite fish can live happily in 5 gallons of water. Read on to learn more about the best fish for small 5 gallon tanks!

Betta Fish

Betta fish, also known as Siamese fighting fish, are one of the most popular choices for 5 gallon tanks. These vibrantly colored fish have long flowing fins and lots of personality. A single male betta is ideally suited for a 5 gallon tank. In fact, most betta enthusiasts recommend no less than 5 gallons for this labyrinth fish. Bettas should not be kept with other bettas due to aggression and fighting. However, they can potentially live with certain small, peaceful tank mates like snails or shrimp. But be cautious of nipping and aggression.

Betta Fish Tank Requirements

Here are the basic tank requirements for keeping a betta in a 5 gallon aquarium:

  • Tank Size – Minimum 5 gallons
  • Heater – Bettas require 78-80°F water
  • Filter – Low flow preferred, or sponge filter
  • Plants – Live or silk plants for hiding and resting
  • Decor – Caves, driftwood, rocks, etc
  • Substrate – Gravel or sand

Proper filtration and heating are especially important for bettas in small tanks, to maintain water quality. Live plants can help absorb waste. Perform partial water changes of 25-50% weekly.

Ideal Betta Tank Mates

The following tank mates can work well with bettas in a 5 gallon, though personalities vary:

  • Snails – Nerite, mystery, etc
  • Shrimp – Ghost, amano, cherry, etc
  • African dwarf frogs
  • Small bottom feeders – Cory cats, otos

Introduce any tank mates slowly and watch the betta’s reaction. Remove immediately if aggression occurs. Avoid fish tank mates with flashy fins or bright colors.


Guppies are another classic nano fish that can thrive in a 5 gallon tank. These livebearers come in a myriad of color patterns and fin shapes. From plain feeder guppies to extravagant show quality strains, you’re sure to find a variety you love. A trio of male guppies or a small group of females makes a nice focal point in a small planted tank.

Guppy Tank Requirements

Here are the basic requirements for keeping guppies in a 5 gallon tank:

  • Group Size – 3-5 guppies
  • Heater – 74-82°F Temperature
  • Filter – Low Flow Preferred
  • Plants – Live Plants for Fry Safety
  • Decor – Driftwood, Rocks, etc
  • Substrate – Sand or Gravel

Provide plenty of hiding spots for fry to avoid predation. Use a sponge filter or baffle the outflow to prevent fry from getting sucked into the filter. Feed a varied diet of flake food, live foods, frozen foods etc.

Ideal Guppy Tank Mates

Good tank mates for guppies in a 5 gallon include:

  • Cherry Shrimp
  • Snails
  • Dwarf Corydoras
  • Ember Tetras
  • Endler’s Livebearers

Avoid aggressive fish like bettas that may nip fins. Introduce tank mates slowly and watch for any aggression or stress.

Neon Tetras

While most tetras need larger tanks, neon tetras are small enough to be housed in a 5 gallon aquarium. A small school of 6 neon tetras makes a colorful addition to a nano planted tank. They are peaceful schooling fish that do best in groups.

Neon Tetra Tank Requirements

To keep neon tetras happy and healthy in a 5 gallon tank, they need:

  • Group Size – At least 6 neon tetras
  • Heater – Water Temp 74-82°F
  • Filter – Low Flow Preferred
  • Plants – Live Plants for Cover
  • Decor – Driftwood, Rocks, etc
  • Substrate – Fine Gravel or Sand

Neon tetras are sensitive to water quality, so regular water changes and filtration are vital. Live plants can help absorb toxins. Feed a variety of small foods like micro pellets, brine shrimp, etc.

Ideal Neon Tetra Tank Mates

Compatible tank mates for neon tetras in a 5 gallon include:

  • Cherry Shrimp
  • Snails
  • Dwarf Corydoras
  • Celestial Pearl Danios
  • Pristella Tetras

Avoid fin-nipping fish like bettas and large aggressive species that may prey on them. Introduce any new fish slowly to reduce stress on the tetras.

Pygmy Corydoras

For the bottom of the tank, pygmy corydoras make excellent nano tank residents. A small shoal of 6 pygmy corys brings activity to the lower levels of a 5 gallon aquarium. They are incredibly petite bottom feeders that stay under an inch in length.

Pygmy Cory Tank Requirements

To keep pygmy corydoras healthy in a small tank, they need:

  • Group Size – At least 6 corydoras
  • Heater – 72-79°F Water Temperature
  • Filter – Low Flow Preferred
  • Plants – Live Plants for Cover
  • Substrate – Fine Sand Substrate

Pygmy corys are sensitive to poor water conditions. Provide plenty of oxygenation and filtration in a 5 gallon. Feed a variety of foods like micro pellets, brine shrimp, bloodworms and algae wafers.

Ideal Pygmy Cory Tank Mates

Compatible tank mates for pygmy corys include:

  • Neon Tetras
  • Celestial Pearl Danios
  • Ember Tetras
  • Chili Rasboras
  • Dwarf Shrimp
  • Snails

Avoid aggressive fish that may pester or nip pygmy corys. Introduce all new tank mates slowly.

Chili Rasboras

Another good nano fish is the chili rasbora, also called the mosquito rasbora. In a 5 gallon tank, you can house a school of 8-10 chili rasboras. They are tiny boraras fish that grow under an inch long and feature a bright red coloration.

Chili Rasbora Tank Requirements

To properly care for chili rasboras in a small tank, provide:

  • Group Size – 8-10 rasboras minimum
  • Heater – 68-77°F Temperature
  • Filter – Low Flow Sponge Filter
  • Plants – Heavily Planted Tank
  • Substrate – Fine Gravel or Sand

Chili rasboras need heavy plant cover and lots of hiding spots. Use low light to help keep these fish less shy. Perform frequent small water changes to maintain pristine water quality. Feed a variety of live and frozen foods in addition to crushed flakes.

Ideal Chili Rasbora Tank Mates

Suitable tank mates for chili rasboras include:

  • Neon Tetras
  • Ember Tetras
  • Celestial Pearl Danios
  • Dwarf Corydoras
  • Snails
  • Shrimp

Avoid housing chili rasboras with aggressive fish like bettas that may attack or eat them. Introduce any new tank mates gradually.

Other Good Options

In addition to the fish already covered, here are a few other species that can work well in a 5 gallon tank:

  • Sparkling Gourami
  • Dwarf Pufferfish
  • Endler’s Livebearers
  • Pea Puffers
  • Celestial Pearl Danios

Tips for Stocking a 5 Gallon Aquarium

When selecting fish for a 5 gallon tank, keep these stocking tips in mind:

  • Choose small species that stay under 2 inches
  • Select schooling fish in proper group sizes
  • Add nano-sized bottom dwellers like pygmy corys
  • Include just one centerpiece or show fish
  • Research compatibility before combining fish
  • Introduce tank mates slowly and watch for aggression
  • Stock conservatively and resist overcrowding

Proper filtration, heating, water changes and tank maintenance become even more critical in small volume aquariums. Lightly stock a 5 gallon and focus on selecting petite species for the best results.

Setting Up a 5 Gallon Aquarium

While a 5 gallon aquarium doesn’t offer much room, you can create an attractive nano tank setup. Follow these guidelines for getting started:

  • Choose a basic 5-10 gallon glass or acrylic aquarium kit
  • Select an adjustable, low flow filter sized for a 5-10 gallon tank
  • Use an aquarium heater rated for 5-15 gallons
  • Add substrate like gravel, sand or aquasoil
  • Include live plants like mosses, anubias and ferns
  • Incorporate small hardscape materials like driftwood and rocks
  • Decorate with nano-suitable decorations and hiding spots
  • Cycle the tank fully before adding any fish
  • Stock with compatible nano fish in proper group sizes

For equipment, simple sponge filters, nano heaters and low flow hang-on-back filters work well. Soil substrates and live plants can help stabilize water parameters in small volumes. Aquascaping hardscapes to maximize space allows for distinct territories. Perform routine maintenance and water changes to maintain a healthy nano ecosystem.

FAQ on Fish for 5 Gallon Tanks

What fish can live in a 5 gallon tank?

Some suitable fish for a 5 gallon aquarium include bettas, guppies, neon tetras, pygmy corydoras, chili rasboras, dwarf puffers, endler’s livebearers and sparkling gouramis.

How many fish can you put in a 5 gallon tank?

A general guideline is 1 inch of fish per gallon of water. So in a 5 gallon aquarium, you can keep about 5 inches of fish. This equates to 5-6 small fish that stay under an inch fully grown, or 1-2 centerpiece fish under 3 inches with nano tank mates.

Is a 5 gallon tank big enough for a betta?

Yes, a 5 gallon tank meets the minimum recommendations for properly housing a single betta. Provide a heater, filtration, plants and decorations like caves in a 5 gallon betta tank. Perform weekly water changes.

Can you put a betta and neon tetras together in a 5 gallon?

While some bettas may tolerate neon tetras, a 5 gallon tank is generally too small to safely house both fish together. Bettas may be stressed or nip fins in such close quarters. It’s better to choose just one or the other as a focal point.

What fish should not be kept in a 5 gallon tank?

Fish that get too large for a 5 gallon include goldfish, angelfish, most tetras, danios, barbs, cichlids, livebearers and rainbowfish. Coldwater fish like goldfish also require space for large filters. Avoid common fish, oddballs and large schooling fish.


While nano fish keeping has its challenges, a 5 gallon tank can make a stunning small-scale ecosystem. Focus on selecting the smallest freshwater fish species suited for life in compact aquariums. Provide excellent water quality, filtration, heating, plant cover and tank maintenance. With the right mix of petite fish, a 5 gallon aquarium can be a desktop showpiece. Just be sure to lightly stock suitable nano fish for a healthy, thriving small tank environment.

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