Information, Freshwater fish

10 Fish Species That Are Ideal For a 30-Gallon Tank

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by Jason Matthews



The 30-gallon tank is an excellent size for fish enthusiasts who want a manageable aquarium that still provides plenty of space for their fish to swim. This tank is larger than other tanks on the market, but not so large that it will take up too much space in your home.

It can be tough picking what fish you want to add to your 30-gallon tank with so many options available, which is why we’ve made this easy guide for you. 

It includes a list of our favorite freshwater fish that come in all sorts of colors and difficulty levels. By the end, you’ll have built an amazing tank full of beautiful fish that will mesmerize you every time you look at it.

Ideal Fish for a 30-Gallon Tank

1. Platies

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Platies are a type of freshwater fish that make great aquarium companions. The platy is a stunning fish that comes in an array of colors and patterns. They grow to about 3 inches, which means each platy needs 3 gallons of tank size—as a general rule of thumb. The peaceful nature of these fish makes them ideal for a thirty-gallon tank.

They’re low maintenance and unlikely to get sick, and you can fit up to 10 platies in a 30-gallon tank. As for their ideal environment, they prefer warm waters with low currents, lots of vegetation, and somewhat hard water that is not too basic. They enjoy eating insects, larvae, vegetables, and supplementary foods like pellets or flakes.

2. Cardinal Tetras

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Cardinal Tetras are brightly-colored, freshwater fish that many people enjoy keeping as pets. They do best in tanks with water of neutral pH and moderate hardness, which should be at least 30 gallons large. It’s worth noting that these fish are quite sensitive to changes in their environment; even small shifts can lead to stress or sickness.

Cardinal Tetras are best kept in small groups of at least 5-6 fish, as they are social creatures who become stressed when isolated. They also don’t do well with other aggressive fish. Growing to about 2.5 inches long, it’s important to make sure they have plenty of space too – aim for a tank that is at least 30 gallons.

3. Molly

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There are around 40 different types of mollies, distinguished by their bodies’ colors. The best ones have black, silver, or bright yellow bodies. Depending on the type you get, it could grow to be about 4 and a half inches long. Keep this social fish in a group of at least 4. They’re relatively small and each needs around 4.5 gallons, so 6 could comfortably live in a 30-gallon tank.

Molly fish make excellent community tank members as they are peaceful and low-maintenance. They are also very flexible and adaptable, able to handle varying water temperatures, pH levels, and hardness levels. Furthermore, they’re omnivores that aren’t picky eaters. So long as the water is clean, these fish will be content!

4. Fancy Guppies

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Fancy Guppies grow to be no longer than 2.5 centimeters and should have a minimum of 30 gallons worth of space in their aquarium. They are such popular fish for people due to both their eye-catching colors and the fact that they don’t need much caretaking.

Fancy Guppies thrive in water that is neutral to slightly acidic, with a temperature range of 72-82 degrees Fahrenheit. They are omnivores and will eat a variety of pellets, flakes, and live foods. When choosing tank mates for Fancy Guppies, it is best to avoid aggressive fish as they are peaceful by nature. To sum up, the Fancy Guppy makes an excellent addition to any 30-gallon tank.

5. Neon Tetra

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The Neon Tetra is a popular freshwater fish for aquariums. It’s a very small fish, usually only growing to 1.5 inches in length, and it originates from the Amazon River Basin in South America. Because of its size, each Neon Tetra should have around 1-2 gallons of tank space per fish.

Neon Tetras are happiest when kept in larger groups, schools of at least 6 fish. They become easily stressed without social interaction and require a 30-gallon tank as a result. Therefore, there should be a community of fish that spend all their time with the school. In general, Neon Tetras are low-maintenance fish compared to other options.

6. German Blue Ram

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The German Blue Ram is a small freshwater fish that tends to grow about 2-3 inches in length. These are typically very peaceful, and are perfect for both community and single-species tanks, but should not be placed with fish much larger than them. A 30-gallon tank is an ideal size, and these fish don’t require as much care compared to other options.

The only drawback of having a German Blue Ram as a pet is that they are prone to developing diseases like Ich and velvet. So, it’s important to monitor their health carefully. Overseeing their well-being is a small price to pay for the enjoyment you’ll get from having this beautiful fish in your home.

7. Red Shoulder Dwarf Cichlid

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The Red Shoulder Dwarf Cichlid is a beautiful freshwater fish that originates from South America.  They need a tank of at least 30 gallons in order to thrive since these fishes are very active and require plenty of space to swim comfortably; thus, why smaller tanks aren’t ideal.

They are very small, only reaching about 3 inches in length when fully grown. Red Shoulder Dwarf cichlids are semi-aggressive, so it’s best to keep them with fish of a similar size in pairs or small groups ranging from 4 to 6 individuals.

8. Celestial Pearl Danio

The silver-colored Celestial Pearl Danio, also known as the Galaxy Rasbora, is a freshwater fish that originates from Myanmar. One of the smallest members of the Cyprinid family, it can grow to be about an inch long. The fish has black spots and an iridescent sheen.

The Galaxy Rasbora should be kept in groups of five or more because they are schooling fish. They are peaceful and can coexist well with other species that share these characteristics. This type of fish prefers clean water that is neutral in pH and has moderate hardness levels. The tank size should have a minimum capacity of 30 gallons.

9. Cory Catfish

Cory Catfish are well-liked fish for freshwater aquariums. They come from South America and can get as big as 4 inches long. They do best in water that is neutral to slightly acidic, not too hard or soft – which makes them suitable for lots of different types of habitats. 

They are social animals so you should keep at least 3-5 together in one group. A 30-gallon tank is more than big enough for a small school of Cory Catfish, which is one aspect that makes these fish appealing. They’re also peaceful and can be kept with other types of fish.

10. Harlequin Rasbora

Harlequin Rasbora
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The Harlequin Rasbora, which only grows up to 2.5 inches long, does best in slightly acidic water with a pH of 6.0-7.5 and needs soft water to thrive. The Harlequin Rasbora is a perfect fish for beginner aquarists or anyone who wants a peaceful community fish. Its small size and low maintenance requirements also make it an ideal candidate for a 30-gallon tank.

The Harlequin Rasbora is a calm fish that feels most comfortable in the company of others. If you’re considering keeping these fish, know that they require a minimum tank size of 30 gallons so they have enough room to swim and socialize with other fish.


At this moment, you should have plenty of ideas for colorful freshwater fish that would look great in your 30-gallon tank. Do some research on the ones you like the best and make sure you can provide them with optimal care so that you can enjoy them to their fullest potential. We hope this article has given you some inspiration. It’s time to get one (or more!) for yourself!

Featured image credit: hadot1, Depositphotos


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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