How Big Do Clownfish Get in an Aquarium?

If your clownfish are treated well and raised in optimal conditions, they will grow between 3-4 inches. This is the same size they are in the wild. 

To ensure they reach their full potential, there’s a lot to learn about raising clownfish in captivity. 

The main things we’re going to discuss are:

  • Clownfish Background
  • Tank size
  • Water requirements
  • Habitat
  • Reef Tank Requirements
  • Tankmates

We’re going to go over everything you need to know to set up your home aquarium for raising clownfish. 

A Little about Clownfish

Before we discuss tank setup, it’s essential to understand where the clownfish comes from.

This way, you’ll understand how to build a tank close to its natural habitat

Clownfish are tropical fish that live in coral reefs. They are most common in the reefs of the Western Pacific Ocean and Eastern Indian Ocean. 

Clownfish live in sea anemones and usually don’t stray too far from these creatures. They hide in the stinging tentacles and rarely go out in the open.

They are omnivores that will eat smaller invertebrates, algae, and occasionally scraps left over from the sea anemone they live in.

Also read: Is Clownfish a Freshwater or Saltwater fish?

Clownfish Temperament

Both in the wild and your home, clownfish are pretty easygoing. This, along with their bright colors, is why they make such popular pets. 

Clownfish are social. In the wild, they live in large groups with other clownfish. There’s one dominant male and one dominant female. 

Clownfish will only show dominant behavior if there is another species of clownfish nearby. Be sure you only choose one to keep in your tank. 

Clownfish are sequential hermaphrodites. If something happens to the female, a male clownfish (usually the dominant male) will permanently become the new female. 

So, if you plan on breeding them, be sure to keep a few clownfish around. 

Tank Size for Clownfish

Clownfish are pretty easy to care for once you’ve set up their tank correctly. 

Because clownish themselves are small and prone to hiding, they don’t need a huge tank.

You could raise them in a 10-gallon, but like any animal, they will thrive with more room. 

30 gallons is the ideal tank size for a pair of clownfish. However, this will change with the number of fish you want to keep and the type of environment you create. 

If, for example, you want several fish, you should add 10 gallons of water for every fish you want.

If you plan on pairing your fish with an anemone, you will need at least a 50-gallon tank. 

Water Requirements

Clownfish need a saltwater environment to survive. The water conditions should mimic what you would find in their natural habitat. 

These are tropical fish that prefer warmer climates. You will need to keep your tank’s water at about 74-79F for the clownfish to be comfortable. 

Install a heater for your tank to keep it at optimal temperatures. You should also have a tank thermometer to observe any changes and adjust accordingly. 

To set up the saltwater environment, your water should be at pH values between 7.8-8.4. 

Clownfish are notoriously bad swimmers, so you don’t want too much water flow as they can’t handle a strong current.

Habitat for Clownfish

In addition to setting up the ideal water temperature and acidity, you’re going to want to aquascape your saltwater tank.

You should try to set up your tank to contain open swimming with plenty of hiding spaces. Fake or real rocks, plants, and even real anemones can all work. 

Clownfish don’t usually live deeper than 40 feet below the ocean’s surface.

The water at these depths is warm (though not as warm as near the shore) and very clear.

This clarity is due to the coral reef, which clears the water of debris and nutrients. It can be challenging to replicate at home, but not impossible. 

Choosing corals and other reef animals is ideal for setting up the clownfish’s aquarium home. 

Reef tanks are gorgeous to look at. You can add brightly colored corals and warm lighting to mimic their closeness to the surface. 

Some ideal (and attractive) corals include the Toadstool, Hammer, and Duncan Corals.

Anemones your clownfish will like to live in are Corkscrew, Leather, Magnificent, and Bubble Tip Sea Anemones. 

You should note, clownfish may choose to adopt one of your corals to live in just like an anemone.

For some corals, the attention will cause them to close off and degrade. 

Be sure to choose a species that can handle attention from fish. 

Reef Tank Requirements

You don’t necessarily need to create a full reef to keep your clownfish happy.

Clownfish can survive without a sea anemone and are perfectly happy hiding in artificial reefs and decorations. 

However, it’s fun to do and makes for a lovely addition to your home.

If you choose to keep coral or anemones, the tank parameters aren’t different from the measurements above. 

First off, you need to pick corals or anemones.

Though they can live near each other in the wild, in your smaller tank, the anemones can sting and kill the corals or other fish. 


Most people pick corals because they are less dangerous. Corals are also usually more colorful than anemones, so they are more aesthetically pleasing.

Corals will require most of the same setup we went over for the clownfish. However, unlike clownfish, they have specific light requirements. 

Even though they aren’t plants, some corals photosynthesize. For example, Bubble Tip Anemones require high-output lighting or LED lights

Corals can grow and reproduce quickly, make sure you have a large enough tank for the species you choose to keep. 

Keep in mind that corals are alive, and you will need to provide nutrients to keep them that way—research ideal food for the species you pick. 

Also read: Can Crushed Coral Be Used in an Aquarium?


If you want to be authentic, anemones are what most clownfish would prefer as a host. Anemones also require good lighting conditions. 

Anemones with Clownfish

The water should be as transparent as possible, just like in a natural reef, so invest in an excellent filter if you want to keep an anemone. 

Levels of ammonia, phosphate, and nitrite should be as close to 0 as possible.

You may want to consider a protein skimmer. Nitrate specifically should be no more than two ppm. 

Anemones (and some corals) move around a reef. Unless you look for specifically micro-reef species, make sure you have room for them to crawl along your tank. 

What are some Good Tank Mates for Clownfish?

If you have a large aquarium, you may want to include some bottom dwellers like Gobies or shrimps.

Because they live on the lowest tank level, they won’t bother your upper-level dwelling clownfish. 

Shrimps (like Harlequin Shrimp) are especially useful because they help break down waste and harmful byproducts. 

Clownfish are overall peaceful and can live with a lot of smaller or similarly sized fish.

Because they are reef dwellers, these fish will also be brightly colored, beautiful tropical fish.

Banggai Cardinalfish, Pygmy Angelfish, Butterflyfish, Yellow Tang, Red Coris, and Dartfish are all viable options. 

Any fish that you would find in the same reefs as the clownfish are good choices, as long as they are legal to keep in your country, city, or state. 

Keep in mind that they do eat some smaller animals, sometimes small crustaceans.

So either purposefully chose their prey or don’t get something you were hoping to keep as a pet.

Species to Avoid keeping with Clownfish

As we mentioned earlier, you should avoid having two species of clownfish in the same tank. They will become aggressive and injure each other. 

You should also avoid any fish that can’t survive the reef environment. Obviously, make sure you don’t try to insert freshwater, open-water, or cold-water fish. 

Some fish won’t interact well with certain corals or anemones. You’ll have to build your tank based on what species you already have or want to have. 

The clownfish doesn’t have a lot of common predators because of their protection from the anemone. However, some larger fish will eat them. 

Natural predators of clownfish, which are also common aquarium pets, include Groupers, Sharks, Lionfish, Eels, and Triggerfish. 

Even though they don’t prey on clownfish, some larger fish, like Angelfish, can be distressing to your clownfish. 

If they feel threatened or like they’re “sharing their space, the clownfish may not want to come out of their hiding spots. 

Final Words

Clownfish will grow to their normal size in an aquarium if you meet their needs. With a little bit of time and a lot of care, they will thrive.

Though it can be hard to get started, once you’ve set up the ideal environment, you can be sure your fishy friends will be happy.

Once you’ve done your research, you can set up the suitable landscape, tank mates if you want other fish, and water parameters to have a mini seascape in your home. 

Reef tanks, in particular, are beautiful adornments to any home. The colorful corals, and bright fish, are a living work of art. 

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