How many fish for a 30-gallon tank: All you need to know

fish for a 30-gallon tank

Unlock the secrets of achieving a balanced happy aquatic aquarium by discovering the ideal number of fish for a 30-gallon tank in this complete guide.

A 30-gallon tank is ideal for beginners. This tank volume has fewer restrictions than other nano tanks. They can house several small fish species along with some medium-sized species.

Read on to discover essential knowledge on how to stock and maintain a 30-gallon aquarium & recommendation of fish for a 30-gallon tank.

30-gallon fish tank

The 30-gallon aquarium provides enough space for a wide variety of fresh and saltwater fish, plants, and corals. The correct dimensions of the equipment can easily be found on various makes and models, making the perfect setup easily achievable compared to other fish tanks.

In this guide, we’ve talked about some of the different ecosystems you can house in a 30-gallon aquarium, and we’ll recommend the solution that’s right for you.

fish for a 30-gallon tank

Overview of a 30-gallon TANK

This tank volume is one of the ideal options for beginners. This volume offers a lot of space for the fauna, while the aquarium doesn’t need much maintenance or space and instead reduces the damaging effect caused by the mistakes that beginners often make. 29 to 30-gallon tanks will provide an ideal ecosystem when adequately designed and maintained.


Marine species are generally more aggressive and territorial. The water in the tank parameters must be very consistent. Saltwater tanks cannot be fully stocked like freshwater ones.

Similar to freshwater fish tanks, when incorrectly stocked, saltwater tank systems can have problems with aggression between their tank mates. In both types of assembly, the parameters must be kept stable at perfect levels for the maintenance of its inhabitants.

How suitable is a 30-gallon tank?

A 30-gallon tank is not a standard size for an aquarium. Your body size can range anywhere between 12 and 18 inches thick.

Some species will thrive in more horizontal spaces, while others need more vertical areas to swim. These aquariums tend to be slightly longer and broader than standard 25-gallons fish tanks. This feature should be considered before planning livestock.

Things you’ll need

30-gallon fish tanks are perfectly sized tanks. When assembling a new project, the fun starts with choosing decorations, subtracts, and inhabitants.

Almost all tropical fish prefer temperatures from 25 to 80 F. Coldwater fish prefer a temperature between 57 and 77 degrees.

Keep a heater to keep the aquarium temperature stable. Have water tests to know the parameters of your tank’s water and make the necessary adjustments. Have an adequately dimensioned filtration system and perform periodic maintenance correctly.

How many fish are in a 30-gallon tank?

For example, your 30-gallon fish tank can accommodate about 20 up to 30 small and medium fish. When calculating the number of fish in your aquarium, be sure to consider the estimated size of each inhabitant as an adult. Do your research before buying new fish.

Guidelines for stocking your 30-gallon fish tank

Aquariums do not come with pre-molded stock lists attached. The factors to be considered to keep stock levels safe are that the aquarium has the entire system assembled, cycled, and well-sized, knowing at least the basics of compatibility between ornamental fish and keeping common sense as to the size of the fish.

The myth about fish size

The idea that a fish can grow to fit into its small aquarium is a dangerous urban legend. In early fish breeding years, people noticed that fish get small in smaller tanks than fish in larger tanks. The small size was to be because of fish waste that accumulated in small tanks, stopping the animal’s growth.

What to know about 30-gallon fish tanks

A 30-gallon fish tank can be an excellent alternative to a large aquarium. Aquariums in this volume allow for a remarkable mix of species and plants.

With the right equipment, the tank will need less care. There are many different types and themes to choose from; you can see some 30-gallon tanks that incorporate driftwood pieces or others with an exciting display with just rocks or plants.

All about 30-gallon fish tanks

The 30-gallon fish tank is a good size and available in many different architectures, meaning it fits in every home, office, or school room.

This is a very versatile tank size and is used for most freshwater or saltwater environments. The 30-gallon tank is much more affordable than larger tanks.

Larger tanks sometimes require extra effort to maintain and are also not easy to install. These types of tanks are also more economical than larger tanks.

Should you get a 30-gallon fish tank?

It’s versatile, easy to clean, and affordable. With such a variety of sizes and materials, the tank can fit almost any space. It is often possible to overstock this tank, so plan carefully. With good planning and scheduled maintenance, the aquarium becomes an excellent addition to any home.

Common problems

The most common problem for a 30-gallon container of fish is overstocking and periodic maintenance. With smaller volumes, water parameters can change dramatically.

It can become dangerous to the fish or very unhealthful. A crowded tank increases the risk of aggression and water degradation; it increases the health risk and illness in the aquarium from excessive waste.

30-gallon tank is easy to maintain when regular water testing and planned cleaning is carried out.

30-gallon fish tank stocking ideas

Small and shoal fish is a great choice. Rasboras are peaceful shoals, perfect for the community. Some catfish like Peckoltia, Panaqolus, and others do very well in aquariums this size.

Shrimps are amazing helpers, and Shrimp Amano and Shrimp Cherry are popular choices. For a small marine reef tank, the clown goby work very well. Banggai cardinalfish are also fantastic in small reef fish ponds.

Clownfish are among the most common saltwater fish, also widely known. If you want to create a marine environment, there are many options.

30-gallon tank setup ideas

One of the most famous tank types is a community tank. This setup allows you to create a community of plants, cute fish, and adorable decorations.

Fish in community ponds are usually small and peaceful. Still, you can keep fish semi-aggressive if your companions are of the same temperament or know how to defend themselves.

With a species – single tank, you don’t have to worry about compatibility.

30-gallon tank maintenance

You must have a proper tank cleaning and water change routine. Regular cleaning of the tank prevents water pollution and degradation of the perfect maintenance of parameters.

Make sure the water is tested regularly. Good maintenance of substrate and equipment is equally essential when cleaning your tanks.

How do I set up a 30-gallon tank?

Setup is relatively simple. It is best if the substrate is at least 1 inch high. In planted or planted aquariums, the substrate must be at least 2 inches.

After setting up the aquarium, leave it in with the filter turned on for a few weeks; this period allows a natural biological filter to establish and create a clean environment for your fish. This cycle lasts approximately four weeks. When nitrogen values are at 0 ppm, you can start adding fish, but little by little.

How many fish can I house in a 29 – 30 gallon tank?

Thirty gallons is a good size, big enough to fit a good number of small animals. Active swimmers and territorial fish could benefit more from having a larger tank or the whole tank to themselves.

How many fish you can house in a 30-gallon tank will depend on the species of fish you want to accommodate. Try to use all the layers of the aquarium, filling with bottom, middle, and surface fish. Keep common sense and think about the size of fish when fully grown.


You can get an automatic or adjustable heater that will be useful to keep the water in your aquarium stabilized in different temperature regimes.

A medium-power heating unit will work without problems; however, there are other functions to consider.

The temperature of your aquarium depends on many factors, including direct sunlight on cooling, insulation and ambient temperature, and many other factors.


Lighting governs fish behavior and can affect behavior and well-being in various situations. It is necessary to provide a natural or artificial light source for the animals to maintain their night and day cycle.

Lighting is also essential when keeping plants; like land plants, aquatic plants also depend on light to grow and develop. The aquarium lamp will make household chores and aquarium maintenance more manageable.

Other equipment

Support can be a table or another stable piece of furniture necessary to support the aquarium. A good quality vacuum will help clean the surface.

Another valuable piece of equipment is an aquarium pump. It helps with in-tank gas exchange and improves filter performance.


Filters help keep the water aerated and free from pollutants. You can use any filter that pumps water through them (external or internal), as long as there is a biological filtration system; It is essential to note this feature when selecting filters.

See our guide to installing a water filter in a fish tank. For more information, see our aquarium filters guide.


Underneath the tank, use a 1/4-inch thick Styrofoam board, thus helping to distribute the weight evenly over the support table.

Wash the substrate well before placing it in the tank. Remember that you must be near the electrical outlet and away from direct sunlight or drafts.

Ask an aquarium expert for advice on how to maintain a natural balance to keep your water healthy. Remember to cycle your tank; a new tank doesn’t have the bacteria that create a stable cycle.

Some ideal schooling fish for a 30-gallon tank

The excellent schools for a 30-gallon tank would be fish like Tetras, Barbs, and Rasboras. These fish usually come in different sizes, ranging from 0.8 to 4 inches in length.

The vast majority of them are relatively resistant, peaceful, easy to purchase, and require little maintenance. It is easy to keep them in a tank of this volume in schools of up to 20 fish.

Neon Tetras

The neon tetra is another tiny aquarium fish, which usually grows to about 1.5 inches in length. These tanks would be enough to store 15-20 neon tetras.

They spend most of their time at school, are peaceful, and make an excellent community aquarium companion. This fish enjoys heavily planted tanks with slightly acidic soft water and a very high temperature. It is a highly low-maintenance fish.

fish for a 30-gallon tank

Cherry Barbs

Cherry barbs are small fish and can grow to 2 inches. These fish are incredibly hardy and are not picky eaters. The cherry barb is known to be one of the calmest fish for a 30-gallon fish tank.

They can live in a wide variety of water conditions, as long as the pond is clean.

Cory Catfish

Cory catfish are bottom dwellers that require a well-maintained tank and water free of pollutants. Some species can grow to 2.5+ inches in length. A 30-gallon fish tank can hold a school of 6 to 10 individuals.

fish for a 30-gallon tank

Can Oscars live in a 30-gallon tank?

The Oscars are native to the Amazon basin across South America, including Colombia, Brazil, Bolivia, and Peru. Most varieties reach a foot in length.

If placed in a 30-gallon tank, this would mean that this fish would take up about 1/3 of the tank’s size and almost its entire width when turned on its side.

It is not recommended to house large fish in less than 125 gals of water. Never buy animals if you are not prepared to keep them properly.


Keep a record of when you’ve added which fish to the tank. Purchase a water testing kit. Keep an eye on the health of the fish. If illness occurs, remove the affected fish as soon as possible to a hospital aquarium.


A 30-gallon fish tank offers an intermediate tank that has more space for experimentation. This is an excellent opportunity for a beginner to learn better and to gain new experiences. These aquariums don’t take up a lot of space around the room.

Combined with gorgeous fish and exquisite design, a tank of 30 gallons is a good investment. If you’re looking for a new tank, this may be the one you’re looking for!

Final Thoughts – How many fish for a 30-gallon tank?

30-gallon aquariums may not be the enormous tanks out there, but they are suitable for the hobbyist. It’s essential to determine if you want a glass or acrylic aquarium; glass tends to be easier to find, significantly smaller, but acrylic is lighter, more transparent, and more durable.

You can even choose from a variety of freshwater and saltwater species that are aggressive or community-friendly, that fit perfectly with this size of the pond.

It can be simple when buying accessories and fauna for your aquarium but always plan your project so that you can avoid many problems.