You have got a 36-gallon tank but are confused about which fish you should get for your tank. Well, worry no more we have got you covered. We’ll go into great depth on the kinds of fish that would be ideal for your aquarium. It’s crucial to take each species’ size, water needs, and compatibility into account when choosing the finest fish for your tank. A 36-gallon tank may be used to build a varied and beautiful aquarium.

Best fish for 36 gallon tank includes Neon tetras, Guppies, Platies, Mollies, Swordtails, Corydoras catfish, and Betta fish but it is crucial to research their individual needs and requirements to provide a healthy and suitable environment for them to thrive and that’s what we are gonna do in this article for you.

1. Neon Tetra

Neon Tetra: Best Fish for a 36 Gallon Tank
Neon Tetra

The first on the list of the 7 best fish for 36 gallon fish tank is the Neon tetra. They are native to South America. Their beautiful red and blue shining colors make them visible long distances. They are peaceful creatures and tend to tolerate each other in a tank. The average lifespan of a neon tetra is around 4-5 years with proper care, although some individuals can live up to 8 years in ideal conditions. This little freshwater fish can grow up to be around 1.5 inches long on average. So a 36-gallon tank can easily accommodate 36 to 40 neon tetras.

Neon tetras are peaceful fish that do well with a variety of tank mates. guppies, platies, mollies, and harlequin rasboras are some of the good options to be kept with neon tetras in a 36 gallon aquarium. Shrimp, such as cherry shrimp or ghost shrimp, help keep the tank clean and add some interest to the aquarium.

2. Guppies

Guppy Fish
Guppy Fish

Guppies are a popular and hardy species of freshwater fish that are known for their bright colors and active behavior. The warm, still waters of Central and South America are their natural habitat. Guppies prefer water that is between 74 and 82°F and has a pH between 7.0 and 7.8. Guppies are little freshwater fish that can grow up to 2-3 inches long at their largest, however, some males can be a little smaller, at approximately 1.5 inches. Male and female guppies typically differ in size and robustness. Because they are omnivores, they will consume flakes, pellets, and tiny live or frozen items.

In terms of tank mates, guppies do well with other peaceful community fish such as tetras, platies, and mollies. They are also compatible with bottom-dwelling fish such as corydoras catfish, and with shrimp and snails.

3. Platies

Platy Fish
Platy Fish

Platies can be centerpiece fish for 36 gallon tanks. They come in a variety of colors, including red, blue, green, and yellow, and are an excellent option for aquarists because of their stunning and unique colors. Females have large sizes as compared to males. Platies’ average lifespan is from 3 to 5 years if provided with a suitable environment. Temperature varies with the type of Platies you have in your fish tank. The Recommended temperature for standard platies is from 75-80°F. The various platies like it cold ranging from 60 to 70°F,

Platies can live in a community fish tank due to their awesome temperament and peaceful nature. Black Neon Tetra and Harlequin rasboras are good choices for keeping them with Platies. But you have to be careful keeping bettas and mollies. They will bully your platyfish. And for cleaning purposes, you can consider keeping Otocinclus Catfish for cleaning algae in the tank as platies hunt down other shrimps.

4. Mollies

Orange Neon
Orange Neon

Mollies are found in the Sothern part of the United State. They are different types of mollies out there but we will talk about only those which are suitable for 36-gallon tanks. They have beautiful colorations like gold, blue, and the most common one the black molly. There is a lot of conflicting information found about mollies so after talking to specialists in this field we are gonna break down these facts for you.

You will find people saying that Mollies are peaceful fish but they can be a little aggressive with other fish in a community tank. It’s important to choose their tankmates after going some research on it. We prefer to keep black Neon Tetras, danios, loaches, and livebearers with our mollies. As far as the water quality is concerned they can live and thrive in soft water as well it’s not necessary to keep them in brackish water.

5. Swordtails

Swordtail Fish
Swordtail Fish

Swordtail can be a super fun addition to your 36 gallon fish tank. Swordtails are social fish and can be kept in a community aquarium with other peaceful fish. They require a minimum of a 20-gallon tank and like to have plenty of hiding spots and swimming space. They are also livebearers, meaning they give birth to live young instead of laying eggs, which can be a fascinating aspect of their care. If you came across a pregnant swordtail remember to give her a good quality environment and feeding to keep your fish out of stress.

Swordtails can be kept with a variety of other peaceful freshwater fish in a community aquarium. They can be kept with Neon tetras, GuppiesMollies, PlatiesCorydoras catfish, Harlequin rasboras, and Zebra danios.


It’s important to note that while swordtails are peaceful fish, they can be aggressive toward their own kind, especially toward other male swordtails. To reduce aggression, it’s best to keep multiple females for every male in the tank.

6. Corydoras Catfish

Corydoras Catfish
Corydoras Catfish

Corydoras Catfish are peaceful, hardy, and active fish that are well-suited for life in a community tank. They are also excellent janitors, helping to keep the tank clean by eating uneaten food and other debris. Corydoras catfish are relatively small fish, typically growing to a maximum length of 3-5 cm. This makes them an ideal choice for a 36 gallon tank, which is on the smaller side of a home aquarium. It’s recommended to keep a group of at least 6-8 Corydoras, as they are social fish and do best in a group. Just be aware of the bioload they generate and make sure to maintain good water quality.

Corydoras are relatively adaptable and can tolerate a range of water conditions, but they prefer a pH of 6.0-7.5, a temperature of 72-79°F, and a water hardness of 2-25 dKH. Corydoras Catfish can live with almost any community fish and snail like Cherry Shrimp, Ghost Shrimp, Amano Shrimp, Malaysian Trumpet Snails, and Rabbit Snails. On the fish side, you can keep them with Harlequin rasboras, Neon Tetras, Swordtails, and Mollies. Corydoras catfish can prove to be the best fish for a 36 gallon tank if looked after with care.

7. Betta Fish

Yellow Betta Fish
Yellow Betta Fish

The last fish in our recommendations for the best fish for a 36 gallon tank is betta fish. Bettas are normally said to be very aggressive and territorial fish but that’s not true in all cases. In fact, with a proper tank setup and compatible tank mates, bettas can coexist peacefully in a community tank. They prefer water with a temperature range of 76 to 82 degrees Fahrenheit and enjoy hiding spots and plenty of plants for them to explore.

Bettas come in a variety of stunning colors and can make a beautiful addition to any aquarium setup. Overall, bettas are a great option for a 36 gallon tank, as long as their habitat and tank mates are carefully considered. Bettas can be kept with Corydoras Catfish, Loaches, Ember Tetras, and Malaysian Trumpet Snails.

Frequently Asked Questions (FAQs)

How many fish can I put in a 36 gallon tank?

It is advised to allocate at least 1 gallon of water for every inch of fully-grown fish as a general thumb rule. Thus, for a 36-gallon tank, you can consider stocking around 36 inches of fully-grown fish. Remember that overstocking can lead to poor water quality and harm the health of the fish, so it’s better to err on the side of caution and keep fewer fish.

Best tropical fish for 36 gallon tank?

Neon Tetra can be the best fish for a 36 gallon tank due to their small, brightly colored, vibrant appearance, and peaceful nature.

How big is a 36 gallon fish tank?

The dimensions of a 36-gallon fish tank can vary depending on the manufacturer and design, but a common size for a 36-gallon aquarium is 36 inches long by 12 inches wide by 16 inches high.


These are our expert’s recommendations for the 7 best fish for a 36 gallon tank. You can choose any of these according to your personal preference as the ideal choice would depend on several factors such as the desired community of fish, the water conditions, and the compatibility of the fish to live in a community tank. However, a commonly recommended fish for a 36-gallon tank is the Neon Tetra. These fish are small, peaceful, and vibrant, and they are known for their bright neon coloration. They do well in groups and in a well-maintained and properly heated aquarium.