There are lots of fish tanks on the market, so the first question is what size tank do you need? A 3-gallon tank is one of the smallest available. It is cheap and fits almost anywhere, but a small volume of water is harder to keep stable, and it is smaller than the 5-gallon minimum most care guides give for a betta.
This guide reviews the 3-gallon kits we link to, plus a few nearby sizes (a 1-gallon, a 3.5-gallon and some 5-gallon kits) that are labeled clearly so you can compare. It also covers setup, equipment, stocking and the jobs a tank this size does well. If you want 3 gallon betta tank ideas, there is a section on that too.
- Tetra Bubbling LED 1 Gallon Starter Kit (a smaller option)
- Marineland Contour 3 Gallon Fish Tank Kit
- GloFish Crescent 3 Gallon Aquarium Kit
TABLE OF CONTENTS
3 Gallon Fish Tanks 101 (Overview)
| PRODUCT | FEATURES | LATEST PRICE |
|---|---|---|
  1. Tetra Curved-Front Aquarium Kit, 5 Gallon (a larger option) |
| Check Price |
  2. Marineland Portrait Aquarium Kit, 5 Gallon (a larger option) |
| Check Price |
| Check Price | |
  4. Koller AquaView Aquarium Kit, 3.5 Gallon |
| Check Price |
  5. Cobalt Aquatics Microvue Aquarium Kit, 5.3 Gallon (a larger option) |
| Check Price |
Not every kit in this guide is 3 gallons, so here is the actual size of each linked product:
- Tetra Curved-Front Aquarium Kit (table row 1) is a 5-gallon kit. It is a larger option than a 3-gallon tank.
- Marineland Portrait Aquarium Kit (table row 2) is a 5-gallon kit. It is a larger option than a 3-gallon tank. The Marineland kit reviewed below is the 3-gallon Contour.
- GloFish Betta Aquarium Kit (table row 3) is 3 gallons.
- Koller AquaView (table row 4) is a 3.5-gallon listing. The one reviewed below is the 3-gallon AquaView 360.
- Cobalt Aquatics Microvue (table row 5) is the 5.3-gallon kit on Chewy. Chewy’s separate “Microvue 10” listing is 2.6 gallons.
- The 1-gallon Tetra Bubbling LED kit linked at the top and in the summary is a smaller option, and we could not confirm the size of the Tetra LED Betta Tank reviewed below.
Generally, the bigger the tank, the more stable the water and the healthier the fish. A 3-gallon tank can cause problems because it is so small, and few fish can be kept in it.
Many new fish keepers assume a smaller tank is easier, but the opposite is usually true. Waste and other pollutants build up quickly in a small volume of water, so more time and effort goes into keeping the water clean.
Dimensions vary by shape. The Marineland Contour kit reviewed below measures about 9.6 x 9.6 x 14 inches, and the Koller AquaView 360 about 10.25 x 10.25 x 14.5 inches. Water alone for 3 gallons weighs about 25 pounds.
A tank this small and light can sit on most sturdy surfaces, but check that the surface can hold the full weight of the tank, water, decor and substrate, and that it is level.
The Best 3 Gallon Fish Tanks Reviewed
Three of the kits below are 3 gallons (Marineland Contour, GloFish and Koller AquaView 360). The Tetra LED Betta Tank is a small kit whose size we could not confirm, and the Cobalt Aquatics Microvue is a 5.3-gallon option if you want more room.
Tetra LED Betta Tank (Size Unconfirmed)
Tetra LED Betta Tank
A compact Tetra LED kit sold for bettas. Check the capacity on the listing before you buy.
We could not confirm this Tetra listing’s capacity or contents. Similarly named Tetra LED betta tanks at other retailers are listed at about 1 to 1.1 gallons, so assume this is a small kit well under 3 gallons unless the Chewy page says otherwise. Check the gallons shown on the Chewy page before you buy. For a betta, look for a tank of at least 5 gallons instead.
Marineland Contour 3 Gallon Fish Tank Kit
Marineland Contour 3 Gallon Fish Tank Kit
A glass 3-gallon tank with rounded corners, an LED rail light and hidden filtration.
This is the Marineland Contour 3-gallon kit. It is a glass tank with rounded corners and measures about 9.6 x 9.6 x 14 inches. The rail light has white and blue LEDs, so you can switch between a daylight look and a moonlight glow. A hinged light and sliding glass canopy let you reach the water to feed the fish.
The kit includes a three-stage hidden filter with an adjustable flow rate, and a filter cartridge. It does not include a heater.
Pros:
- Glass tank that resists scratching.
- Adjustable filter flow.
- Daylight and moonlight LED settings.
- Hinged light and sliding canopy for access.
Cons:
- No heater is included, and a hidden filter limits where one can go.
- Even at the lowest setting, the filter flow may be too strong for a Betta.
- At 3 gallons, it is below the usual betta minimum.
GloFish Betta Aquarium Kit, 3 Gallon
GloFish Betta Aquarium Kit, 3 Gallon
A 3-gallon GloFish kit sold for bettas, with LED lighting and an internal filter.
This kit is a simple first tank for a beginner or a child, and it fits easily on a desk or in a bedroom. It includes the aquarium, a clear cover, white and blue LED lighting with a moonlight mode, and a Tetra Whisper internal filter with a Bio-Bag cartridge.
Gravel, plants, decor, a heater, a dechlorinator and a thermometer are extra.
Pros:
- Includes tank, cover, light and filter.
- White and blue LEDs with a moonlight mode.
- Compact enough for a desk.
Cons:
- A heater is not part of the kit, and bettas need one.
- The blue lighting is designed to show off GloFish colors, not natural plant growth.
- At 3 gallons, it is below the usual betta minimum.
Koller AquaView 360, 3 Gallon Aquarium
Koller AquaView 360 3 Gallon Aquarium
A cylindrical 3-gallon tank with LED lighting and a power filter.
This is the 3-gallon Koller AquaView 360, a cylindrical plastic tank that measures about 10.25 x 10.25 x 14.5 inches. The kit comes with a power filter and LED lighting in seven color choices.
A round plastic tank has no hard glass edges to bump, which makes it a reasonable first tank for children.
Pros:
- 360-degree view of the tank.
- Plastic tank, lighter than glass and less fragile.
- Includes a power filter and LED lighting.
Cons:
- The cylindrical shape makes it harder to arrange decor.
- Not ideal for fish that need horizontal swimming space.
- Plastic scratches more easily than glass.
Cobalt Aquatics Microvue, 5.3 Gallon (A Roomier Option For A Betta)
Cobalt Aquatics Microvue Aquarium Kit, 5.3 Gallon
A glass betta-friendly kit. Chewy lists this version as 5.3 gallons.
The Chewy listing for this Microvue kit is for the 5.3-gallon size, so it is larger than the other tanks in this section. That makes it a better fit for a betta, since 5 gallons is the minimum most care guides give. It is a glass tank kit with an internal filter and LED lighting, and it suits a desk or counter.
Bettas are small and do not outgrow a 5-gallon tank.
Pros:
- Glass tank.
- Meets the 5-gallon minimum for a betta.
- Compact footprint for a desk or counter.
Cons:
- You will need a heater for a betta or other tropical fish.
- The listed size is not 3 gallons, so check the dimensions against your space.
3 Gallon Fish Tank Equipment
Starting a tank takes more than filling it with water and adding fish. Some kits include everything you need, but most leave out at least a heater, a thermometer and a dechlorinator.
Here is the equipment you will need:
Filter
A tank is not complete without a filter. The filter removes waste, uneaten food and other pollutants, and the flow of water through the media supports the bacteria that break down ammonia.
This matters more in 3 gallons, where pollutants build up fast. Follow the manufacturer’s schedule for rinsing and replacing media. If you keep a betta, choose a filter with adjustable flow or a sponge filter, because betta fish with long fins struggle in a strong current.
Heater
Tropical fish need a heater. Bettas do best at around 78 to 80°F and become sluggish and stressed in cooler water, so a heater is not optional for a betta.
Use a small, adjustable heater rated for a tank of this size. A common rule of 3 to 5 watts per gallon works out to roughly 10 to 15 watts for 3 gallons. Check the heater’s tank-size rating, because many small heaters are rated higher, and a heater that is too strong can overheat a tiny tank.
Lights
Most fish do better with a regular day and night cycle, so a simple LED light on a timer works well. If you keep live plants, the light needs to be strong enough for them to grow, and many kit lights are not. Check the plants you want before you buy.
Other Equipment
Tanks this size don’t usually come with a stand, since they can sit on most surfaces. Choose a level, sturdy surface that is bigger than the base of the tank.
A tight-fitting lid or hood is important too, because it stops fish jumping out of the top.
Cover the bottom with about an inch of substrate. Gravel is usually fine, but some bottom-dwelling fish prefer sand. Add a few decorations, but leave most of the space open for swimming, because there is little room to spare.
A thermometer is useful for checking the temperature. Place it at the opposite end to the heater for the best estimate of the overall temperature.
Cleaning equipment such as an algae magnet and a gravel vacuum helps during cleaning sessions, and a fish net is the easiest way to move fish. Any water you add must first be treated with a dechlorinator, to remove the toxic chlorine and chloramine in tap water.
Best Fish For 3 Gallon Tanks
Only a very small selection of fish suit a 3-gallon tank, and none are ideal. A tank this size works best for shrimp and snails.
Fish need to be small enough to fit comfortably or they will become stressed and/or diseased. Each fish you add also needs its own space.
Juveniles of larger fish seem like a workaround, but they outgrow the tank and need to move to a bigger one.
Here are the fish people commonly suggest for small tanks, and the catch with each:
- Otocinclus – These small algae eaters are schooling fish and are usually kept in groups of at least five or six, which is too many for 3 gallons.
- Guppies – They come in lots of colors, but they breed quickly and a 3-gallon tank fills up fast.
- Neon Tetras – This is one of the most iconic aquarium species. They shoal to produce some bright colors, but a group should be at least six, which is too many for 3 gallons.
- Zebra Danios – These hardy fish are good for beginners, but they are very active and need a group of at least eight to ten in a much bigger tank. Seriously Fish gives a base of 90 x 30 cm (about 21 gallons) as a minimum.
- Bettas – They must be kept singly, since males are aggressive. A betta needs at least 5 gallons, so 3 gallons is below the usual minimum.
Ideally, any fish you keep needs a larger tank than 3 gallons to stay healthy.
Invertebrates are a better fit, because they don’t swim around as much. Dwarf shrimp such as cherry shrimp or Harlequin shrimp can be kept in a small group, and a starting group of 5 or 6 is common. Small snails such as ramshorn snails can be kept in similar numbers. Shrimp and snails still need a cycled tank, so don’t add them to a brand-new setup.
You could keep invertebrates in a 3-gallon tank. In fact, they will be much more comfortable than fish because they don’t move around as much.
Dwarf shrimp like Harlequin or cherry shrimp can be kept in groups of 5-8. Small snails, like ramshorn snails, can also be kept in similar numbers.
3 Gallon Fish Tank Ideas
A 3-gallon tank is too small for most fish, but it has plenty of other uses.
1. 3 Gallon Betta Tank Ideas
If you already have a betta in a 3-gallon tank, or you have no room for anything bigger, these changes make it more livable. Plan to upgrade to 5 gallons or more.
- Use a heater and keep the temperature steady at around 78 to 80°F.
- Use a gentle filter, such as a sponge filter, or turn the flow down. Long fins and strong currents don’t mix.
- Add live or silk plants with soft leaves, plus a cave or a hide. Avoid sharp plastic decor that can tear fins.
- Keep a tight lid on the tank. Bettas jump.
- Do small, frequent water changes and test for ammonia, since a small volume of water fouls quickly.
- Keep the betta alone. No tank mates, and no second betta.
2. Nano Tank
This is a term for small aquariums. There is no strict definition, but nano tanks are generally less than 10 gallons.
Only small species will fit in a nano tank, and you can’t keep many individuals. In a 3-gallon nano tank, shrimp and snails are a better fit than fish.
3. Quarantine Tank
Disease can spread quickly through a tank. If you suspect a fish is sick, move it to the 3-gallon tank. The sick fish is isolated, so it can’t spread the disease, and you can treat it without dosing the main tank. Once it has recovered you can move it back.
Quarantining new fish before adding them to your main tank is also safer if you are unsure about their health. A 3-gallon tank only works for small fish.
4. Breeding Tank
Small tanks make good breeding tanks because most of the fish will be fry or juveniles, so they are small enough to be comfortable in 3 gallons.
If one of your livebearers is pregnant, you can move her to the 3-gallon tank until she gives birth. The fry will need to be moved once they have outgrown the tank.
5. Live Food Culture
A small tank can be used to culture live foods such as brine shrimp or daphnia for your larger fish. Feeder fish are a riskier choice, since they can carry disease.
6. Paludarium
Another option is trying a paludarium. Instead of mixing plants and fish, you remove the fish and fill the space with a dense collection of plants.
You still need to think about the space your plants need. If you pack them too densely, they will compete with each other for light and nutrients.
Frequently Asked Questions
How Many Fish Can I Keep In A 3 Gallon Tank?
Very few. A betta kept on its own is the most common choice, although most care guides say bettas need at least 5 gallons. Shoaling fish such as neon tetras need a group of at least six, so they don’t fit.
Can A Betta Live In A 3 Gallon Tank?
A betta can survive in 3 gallons if the tank is heated and filtered, but most guides recommend at least 5 gallons, and Seriously Fish suggests around 11 gallons. A bigger tank is easier to keep clean and warm.
Should I Use A 3 Gallon Tank?
This size is too small to keep most fish in over long periods. There usually isn’t enough swimming space, and some species outgrow it as they mature.
There are other ways to use the tank, though. Three gallons is enough for a quarantine tank, a small breeding tank, a live food culture or a shrimp tank.
Summary
Tetra Bubbling LED 1 Gallon Starter Kit
A 1-gallon acrylic Tetra kit with a bubbling LED light, filter and air pump. It is a smaller option than a 3-gallon tank, so it suits only a very small setup.
If you are starting a new aquarium, get the largest tank you can afford and fit. A bigger tank is easier to maintain, gives you more choice of fish and gives your fish more room. For a betta, aim for 5 gallons or more.
A 3-gallon tank is best used for short-term jobs. Maybe your fish keep getting pregnant and you need somewhere for the babies to be born safely, or a fish is sick and you need to isolate it to protect the others. A 3-gallon tank fills these roles well.
Before purchasing, think about both your needs and the needs of the fish.
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