5 gallon fish tanks make excellent aquariums.
Don’t let someone convince you otherwise.
I hear a lot of advice that goes something like, “for the price of a 5 gallon tank you could get a 10 gallon and have more fish.”
And that is often true.
But, sometimes, a 5 gallon tank is the better option for your apartment or home and may look better, aesthetically, than a basic 10-gallon tank.
And, in my experience, a smaller aquarium forces you to make more meaningful choices about design and which fish to keep.
So, if you think a 5 gallon tank is right for you, don’t listen to the naysayers and read on to discover what I consider some of the best fish for a 5 gallon tank.
Also, let me point out that most schooling fish are not “ideal” for a 5 gallon.
The issue is that schooling fish feel more stressed when alone or in a small group.
And in a 5 gallon tank, small schools (typically 4-5 fish) are pretty much the maximum you can have unless you want to risk an ammonia spike.
But, I have still included some schooling fish on this list of best fish for a 5 gallon because, in my experience, they are beautiful and more than happy to live in a 5 gallon if given the proper conditions.
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1. Betta Fish (Betta splendens)
78–80 degrees Fahrenheit (25-27 degrees Celsius)
Betta fish, both males and females, are truly some of my favorite fish.
They have attitude, they stare at you inquisitively, and they look stunningly beautiful.
They also hate other betta fish, and a lot of other aquarium fish too, so having them in their own 5 gallon is perfect.
Female betta fish should also be a serious consideration for your 5 gallon aquarium.
Female betta fish, especially koi bettas, are just as feisty as male bettas but have shorter fins, which gives them an agile and streamlined look, like a colorful torpedo.
If you want to learn more about the differences between female and male bettas, check out my article on female vs male betta fish.
A betta fish is my top pick for a 5 gallon aquarium because you get personality, looks, and intelligence all in one fish.
Betta fish are relatively easy.
A heater and a sponge filter (betta fish do not like currents) along with a light is all they need to thrive in a 5 gallon tank.
The equipment below is what I use in my own betta tanks:
2. Guppies (Poecilia reticulata)
74-80 degrees Fahrenheit (23-27 degrees Celsius)
A tank of about 4 male guppies will create a flurry of activity during feeding and flashes of color every time you walk by.
Guppies are much more energetic than betta fish and are better for those who want to see fish swimming against the glass with excitement for their next meal.
Male guppies come in a huge range of colors, from bright red tails to panda-like coloring.
While female and male guppies can be kept together without aggression, your 5-gallon tank will quickly become filled with baby guppies (trust me, they make a lot of babies!).
If your plan is to have a display tank or planted tank, stick with a group of your favorite males.
3. Cherry Shrimp (Neocaridina davidi)
72-80 degrees Fahrenheit (22-27 degrees Celsius)
Cherry shrimp are still underrated in the aquarium hobby.
These freshwater shrimp are colorful and extremely enjoyable to watch as they search for algae and food.
Unlike fish, cherry shrimp do not create a large bioload, meaning they do not produce much waste and so your water quality will not degrade as much when you add new shrimp.
This means that you can have 15-20 cherry shrimp in a 5-gallon tank without worrying about the sudden ammonia spikes that the same number of fish would create.
So, cherry shrimp are really one of the best “fish” for a 5 gallon tank.
Also, cherry shrimp are for beginners; don’t let someone tell you that they are for intermediate aquarists only.
Cherry shrimp thrive under the same parameters and care as betta fish or guppies and are hardier than you may think.
I use tap water for water changes in my cherry shrimp tanks and they do not mind that at all (no RO water necessary for cherry shrimp).
4. Mollies (Poecilia latipinna/Poecilia sphenops)
76-80 degrees Fahrenheit (24-27 degrees Celsius)
Mollies are a classic freshwater aquarium fish and have been in the hobby for a long time.
They are also livebearers like guppies and will produce baby mollies at an alarming rate.
Balloon mollies, red one in particular, are lively and full of personality.
A 5 gallon tank can easily handle a group of about 5 male mollies.
The tank setup you need for mollies the essentially the same as for the other fish in this article.
A heater, sponge filter, and light are the main essentials.
5. Pygmy Corydoras (Corydoras pygmaeus)
74-79 degrees Fahrenheit (23-26 degrees Celsius)
Corydoras or cory catfish are small bottom dwelling freshwater catfish.
Cory catfish prefer to be in schools and 5 gallon tanks don’t provide most species of corydoras with enough room.
But, thankfully, a nano species of cory catfish exists.
Corydoras habrosus, Corydoras hastatus, and Corydoras pygmaeus are three species of cory catfish that only reach about an inch in length.
But, they may be hard to find as these nano fish have become increasingly popular.
Keeping 5 of these cory catfish in a 5-gallon tank is doable but make sure you provide frequent water changes to avoid waste buildup and potentially disastrous ammonia spikes.
These minature cory catfish are truly fun to watch as they zoom around the bottom of your tank. and
They make an excellent addition to any planted tank and can be one of the best fish for a 5-gallon tank if you maintain their water quality and avoid overfeeding.
A sponge filter is ideal for these small cory catfish because these filters do not produce strong suction or water currents.
6. Neon Tetras (Paracheirodon innesi)
74-80 degrees Fahrenheit (23-27 degrees Celsius)
Neon tetras look like a science experiment involving jellyfish and minnows.
But, the colors and glow of the neon tetras is, in fact, natural and helps these fish stand out in the muddy waters of their native environment, the Amazon basin of South America.
For a 5 gallon planted tank, consider a school of no more than 5 neon tetras.
Neon tetras are tend to be nervous fish and definitely thrive in bigger tanks, but actually make excellent fish for a 5 gallon if given plants and some décor for hiding.
The bright colors of neon tetras will contrast especially well with a dark substrate and deep green leaves, like those of Anubias plants.
If you plan on getting more than 5 neon tetras, considering upgrading to a larger tank, like a 20 gallon long.
7. Harlequin Rasbora (Rasbora heteromorpha)
74-82 degrees Fahrenheit (23-28 degrees Celsius)
Harlequin rasboras have an orange hue and a striking black mark about halfway down their body.
Harlequins make excellent display fish for planted tanks and aquascapes because they add contrast to a tank as well as visual appeal.
But, Harlequin rasboras, like neon tetras, prefer to swim in dense schools.
This makes Harlequins less than ideal for a 5 gallon tank but, with frequent maintenance and water changes, a small school of no more than 4 fish can be kept happily.
If you plan on keeping more than 4 Harlequins, consider upgrading to a 20 gallon long as the water quality in a 5 gallon will degrade relatively quickly.
Fish Not to Have in a 5 Gallon Tank
Goldfish are beautiful creatures but a 5-gallon tank is too small.
Goldfish are big waste producers and water quality can quickly reach a danger zone in a 5 gallon tank.
If you want to keep goldfish, consider keeping them in a small patio pond or get yourself between a 20 gallon and 40 gallon tank.
Angelfish are stunningly beautiful but become far too large for a 5 gallon aquarium.
Angelfish like being near other angelfish but will fight each other without adequate space.
They also tend to be nippy toward other fish.
3. Other Cichlids
Cichlids, like Oscars, Jack Dempseys, Green Terrors, and countless others, make poor residents for 5-gallon tanks because they grow big and tend to be extremely active.
Also, most cichlids are territorial and need extra room if kept together in a tank.
If you know you want to be a cichlid keeper, definitely skip the 5-gallon tank and go straight to a 20 gallon or larger.
A 5 gallon tank is for someone who likes a challenge.
With limited space, choosing the best fish, plants, and decorations becomes a game of chess.
Putting too many fish in a 5 gallon can quickly lead to a tank crash and the demise of your fish.
But, a thriving 5 gallon aquarium is a work of art.
If you want to learn about aquascaping a small tank, check out my step-by-step guide on creating a 5 gallon cave aquascape.
Larger tanks, like a 20 gallon long are also fun, especially if you want to keep multiple species of fish, but if you crave the challenge of building a vibrant and intricate ecosystem, consider getting a 5 gallon aquarium and filling it with plants.
For more information about plants that can thrive in a 5 gallon tank, check out my article on almost unkillable aquarium plants.
If you want to learn about setting up an even smaller tank, check out my step by step guide to aquascaping a 3 gallon betta bowl.
The reward of small tanks comes from the effort and care we put into them.
As always, stay zen aquarists.