How Many Clownfish In A Tank? Answer For All Species And Tank Sizes

Mar 14, 2022

How Many Clownfish In A Tank?

When Finding Nemo was first aired in 2003, clownfish were thrust into the limelight overnight. Needless to say, they became the iconic poster child of the saltwater fishkeeping hobby. 

Even today, millions of clownfish are caught from the wild every year and sold in the ornamental fish trade. Used to the endless choppy waters of seas and oceans, these fish are forced to lead a life in confinement in a span of a few days. 

Therefore, the least we can do as responsible fishkeepers is to provide ample space for these orange-bodied fish. We can never even dare to emulate the greatness of their natural homes, but we can always help them lead the best lives possible in captivity. 

And thankfully, you don’t have to go to great lengths to do so. Instead, providing ample swimming space, clean and clear water, a well-rounded diet, and a stress-free environment are the 4 pillars of successfully raising clownfish. 

Today’s blog will discuss 1 of these 4 factors: providing ample swimming space. How many clownfish in a tank is possible? How do the size of the tank and species of your clownfish come into play? 

That was one long intro. My apologies for it. Now, let’s dive right in. 

How Many Clownfish In A Tank?

Frankly, this question is quite vague. How many clownfish in a tank depends on factors like how big the tank is and what clownfish species you intend to keep. However, the rule of thumb in the hobby is to keep 1 pair per tank to keep unsolicited bullying and aggression under check. 

If you want to keep any more than 2, you should aim to house at least 5-6 of these fish together. This way, the aggression that the mated pair will lash out on singletons will be spread out. 

If a single fish has to bear the brunt of the mated pair’s hostility, there’s a good chance the singleton will bite the dust. 

In the wild, clownfish live in a group of 5-6 fish that share a single anemone. 

The group consists of a female (the biggest fish in the bunch), a breeding male (the second biggest fish in the bunch), a couple of sexually immature males that lead subdued lives and have no role in reproduction.

All in all, these fish have an incredibly complex size-based hierarchy that even we, the self-proclaimed most advanced breed on the planet, find baffling.

If you were to recreate this setup in your home, you’d need a colossal tank, to begin with. In my opinion, you’d at least need a 150-gallon tank or upwards. 

And as you are already aware, maintaining a saltwater tank that big comes with a hefty price tag. 

Therefore, it’s wise to stick to just a pair of clownfish per tank. 

There are at least 30 different clownfish varieties – and some of them are poles apart from each other. 

While some like ocellaris and percula clownfish sport a happy-go-lucky attitude, others like maroon and clarkii clownfish are legendarily ill-tempered. 

These fish are pretty varied in terms of size as well. While some barely make it past 3 inches, others easily reach 6 inches long. 

We will discuss the minimum recommended tank size for different clownfish species below. But before that, let’s quickly have a look at what other hobbyists have answered the question, “how many clownfish in a tank?”. 

Note that all of the answers shared below purely belong to the respective authors. My only intention here is to help you make an informed decision. 

So, let’s see what they’ve to say. 

How Many Clownfish In A Tank? Real Answers By Real People!

“You might get away with keeping more than 2 at first, but once the pair gets closer to breeding, it’s going to be lights out for the rest of the clowns.”

“You will come across a very few examples of people successfully keeping multiple pairs in the same tank for a certain time, but it almost always plays out poorly.”

“It’s pretty rare to see multiple pairs or even 3 clowns in the same tank in the long term.”

“Keeping multiple pairs could work with very young percs or occys for a year or two. But once these fish grow big enough to breed, it’s the onset of the great clownfish war.”

“You can keep just one pair unless it’s for a short term or all the fish come from the same clutch. But, remember, there’s a very fine line between owning your tank and your tank owning you.”

“Just 1 pair of clownfish per tank for real.”

“The rule of thumb is just 1 pair of clownfish per tank. Unless you have an absurd amount of space, I wouldn’t dare to go against the grain.”

“From what I have read, you can just keep 2 clownfish unless you have a super big aquarium length-wise.”

“I wholeheartedly agree on the general rule that you should keep 1 pair per tank unless the tank is absolutely big. I tried adding a second pair to my 240-gallon tank, but they were significantly harassed. 

They’re now relocated to the refugium. The old folks, who are now 17 years old, still live in the main tank.”

See, I didn’t deliberately choose the answers that fit my narrative and pasted them here. 

I admit there were a few exceptions, like one person housing 2 percs and 2 occys in a 40-gallon breeder, but an overwhelming number of hobbyists shared that the safest and the most practical bet here is to keep just 1 pair per tank. 

Recommended Readings!

Do Barracudas Eat Clownfish? Or Are They Innocent?

Black And White Clownfish Care Guide | Diet, Habitat, Breeding, Accessories 

Do Clownfish Mate For Life? How Finding Nemo Should Have Ended?

Can You Have 3 Clownfish In A Tank?

Yes, you can keep 3 clownfish in a tank for a very short time. Once a pair forms and they get ready to breed, the duo will bully the lone fish to the point it kicks the bucket. 

I wish I was exaggerating or kidding. However, keeping 3 clownfish together in the same tank is a super bad idea unless you’re OK with at least one fish biting the dust. 

Can Clownfish Live Alone?

Clownfish don’t thrive when kept alone as bettas do. However, they can live alone and lead a solitary life. In fact, many hobbyists first dabble in the hobby by raising a single clownfish.

When you keep a pair of clownfish, there will definitely be some level of aggression before they pair up. Even worse, they may not pair up at all. 

Therefore, most new hobbyists choose to keep just 1 clownfish at a time. However, from what I read on forums, clownfish aren’t very active or playful when kept alone. 

That’s why, once you garner enough confidence and experience, add another clownfish to your tank. 

Do Clownfish Need To Live In Pairs? 

Clownfish don’t necessarily need to live in a pair to thrive, but they’d most definitely benefit from having a partner. Keeping a couple of clownfish is the preferred choice for most hobbyists. 

If you keep two sexually immature clownfish in a tank, the pair will fight until there is one clear winner. The winner will gradually transition into a female and will be the assertive one among the two. The loser will probably become the breeding male if the duo pairs up. 

However, if they don’t pair up, the alpha female will make life straight-up miserable for the male. 

Can You Keep More Than One Clownfish Pair In A Single Tank?

As you can tell from all the quotes mentioned above, it’s never ever a good idea to keep more than 1 pair in a given tank unless you really know your way around clownfish or can manage a humongous tank with multiple anemones. 

If you keep multiple pairs of clownfish in the same tank, your tank will soon be a playground for frequent stand-offs against different teams. The situation gets even tenser if they have to compete for an anemone. 

And this is not amusing at all. 

It’s a matter of life and death. Unfortunately, the losers can be bullied and tormented to the point of death. 

If you do not like chaos, it’s best to stick to a single pair. 

But if you’re bent over backward to raise more than two, you can do so in a separate tank or use a tank divider available on Amazon. 

How Many Gallons Does A Clownfish Need?

There are over 30 different clownfish varieties. And they are all quite different from each other in terms of size and temperament. 

Therefore, the answer to this question ranges from 20 to 70 gallons. For example, peaceful and moderately-sized clownfish like percula need 20 gallons of water per fish, whereas large species, like blue-striped clownfish that grow over 7 inches, demand 70 gallons per fish. 

You can then allocate 10-30 gallons of tank space for every new addition. 

Since we can’t generalize and make a sweeping statement, I’ll answer the space requirement for different clownfish species below. 

How Many Gallons Does A Percula Clownfish Need? 

Perculas are among the smallest clownfish species we know – reaching only around 3 inches long as adults. Although I have often seen this fish subjected to nano tanks, the minimum recommended tank size for a single percula fish is 30 gallons

You can then allocate 10 to 15 gallons extra for each new addition. 

How Many Gallons Does An Ocellaris Clownfish Need?

Nemo that we all know and love is based on an ocellaris clownfish. These fish, too, are petite like perculas and grow just as big as perculas – 3 inches. 

However, ocellaris clownfish have a friendlier demeanor than their cousins, perculas. 

Therefore, the minimum recommended tank size for ocellaris clownfish is 20 gallons. Once again, you need to allocate 10 to 15 gallons extra for every new addition. 

How Many Gallons Does A Maroon Clownfish Need?

Maroon clownfish are one of the bigger specimens in the lot – reaching about 6 inches long as adults. And don’t even get me started about their temperament. They’re as feisty as they come. 

Thus, a single maroon clownfish’s minimum recommended tank size is 30 gallons. If you plan to keep a pair, you’d at least need a 55-gallon tank. 

How Many Gallons Does A Tomato Clownfish Need?

Tomato clownfish are only slightly smaller than maroon clownfish – reaching about 5.5 inches long. These fish, too, are known for their angry disposition – especially as they get older. 

Hence, tomato clownfish require at least 30 gallons of space for a single fish. You can then allocate an additional 10-20 gallons for every new addition. 

How Many Gallons Does Clarkii Clownfish Need? 

Clarkiis are amongst the meanest clownfish we know. Even more, their anger reaches extreme heights as they get older.

Thus, even though they only get 4 inches long as adults, the minimum recommended tank size for a single clarkii clownfish is 30 gallons

And it’s never ever a good idea to keep more than a pair of clarkiis in the same tank irrespective of how big your tank is. 

How Many Gallons Does A Pink Skunk Clownfish Need?

Pink skunk clownfish are just as pretty as their names. Like clarkii clownfish, these fish get only around 4 inches long. They’d score only 1 or 2 on a clownfish aggression scale of 1 to 10, with 10 being the most aggressive. 

These fish require 30 gallons of tank space for a single fish. For every new addition, you will need to allocate 15 gallons more. 

How Many Gallons Does An Oman Clownfish Need?

Oman clownfish are one of the largest and rarest clownfish to exist. But they’re not everyone’s cup of tea. These fish grow about 6 inches long and are notorious for their anger. 

On a scale of 1 to 10, with 10 being the most aggressive, these fish would easily score 8 or 9. 

The minimum tank size for a single oman clownfish is 30 gallons. Owing to their hostile disposition, you would then want to allocate at least additional 20 gallons for each new addition. 

How Many Gallons Does A Saddleback Clownfish Need?

Saddleback clownfish are among the big ones. These fish grow about 5 inches long. But they’re gentle giants. They are relatively peaceful and will seldom annoy other tankmates. 

Despite their friendly demeanor, these fish require 40 gallons of tank space owing to their big size. You can then ration 15-20 gallons of tank space per new addition. 

How Many Gallons Does An Allard’s Clownfish Need? 

Allard’s clownfish grow around 5.5 inches long. And since these fish belong to the clarkii complex, they’re naturally short-tempered and mean. And a big, mean fish is an obvious red flag. 

Therefore, these fish need plenty of space. You need to provide at least 50 gallons of tank space for a single Allard’s clownfish. For every new addition, allot 20 gallons more. 

How Many Gallons Does A Blue-Striped Clownfish Need?

Blue-striped clownfish grow 7 inches long. And they’re mean and territorial. They will display aggressive behavior towards any other fish present in the tank. And guess what? Their temperament only gets worse as they age. 

Thus, you need to ensure about 70 gallons of tank space for a single blue-striped fish. That’s quite a lot! 

How Many Gallons Does A McCullochi Clownfish Need?

McCullochi clownfish are among the rarest clownfish species we know due to their minimal natural range. These fish attain a maximum length of 4.7 inches.

Although these fish don’t grow as big as blue-striped clownfish, they still require 70 gallons of tank space for a single fish. This is because these fish are among the most aggressive clownfish species we know. 

The Risks Of Keeping Clownfish In A Small Tank

From the segment above, I think it’s clear that clownfish are not meant for smaller tanks. Marketing gimmicks often advertise clownfish to be suitable for nano tanks sized 2 or 5 gallons, but even the minimum requirement for the smallest of clownfish is 20-30 gallons. 

When you keep your clownfish in a small tank, you aren’t just impairing the fish’s life but also allowing the tank to own you. And I say that because small tanks are treacherous. They are hard to maintain. Both you and your fish will end up in a stressful situation. 

Parameters Become Toxic Quickly And Change Suddenly 

Saying small tanks are treacherous would be an understatement. Given the small volume of water, parameters like ammonia and nitrite levels will become toxic in no time and change without warning. 

Toxic buildup in the tank will happen soon and often. Also, the slightest change in one corner of the tank will be felt throughout the tank in a jiffy. To put it simply, a small tank will keep you on your toes constantly. 

Both You And Your Fish Will Be Stressed 

Remember what I said earlier about you owning the tank or the tank owning you? Since parameters are super prone to change and reach dangerous levels in small tanks, you need to monitor them constantly. And no matter how hardy a fish is, it doesn’t tolerate sudden changes. 

The end result? Both you and your fish will produce the stress hormone cortisol in excess. And it will, in turn, suppress the appetite and attack the immune system. 

Your Fish May Experience Stunted Growth 

Small tanks stunt a fish’s growth in one too many ways. First, your clownfish will not get enough exercise. This can lead to grim conditions like muscle atrophy. 

Second, small tanks will stress your fish constantly by changing the parameters suddenly or making them toxic quickly. This will naturally compromise your fish’s immune system and make it susceptible to an array of pathogens waiting for the golden moment to strike. 

Frequently Asked Questions 

Credit: Rickard Zerpe (CC License)

How Many Clownfish In A 5-Gallon Tank?

Even the smallest of clownfish species cannot live inside a 5-gallon tank. I know percula and ocellaris clownfish are often marketed as fish suitable for nano tanks, but that’s far from the truth. 

Unfortunately, you can keep 0 clownfish in a 5-gallon tank. 

How Many Clownfish In A 10-Gallon Tank?

Once again, the answer is 0. You can keep exactly 0 clownfish in a 10-gallon tank. I have seen hobbyists keep 1 or 2 (mostly ocellaris or percula) clownfish in a 10-gallon tank, and I absolutely condemn this kind of practice. 

10 gallons is simply not enough for any clownfish to thrive in and lead a happy life. 

How Many Clownfish In A 20-Gallon Tank? 

You can keep clownfish that doesn’t grow over 3 inches long in a 20-gallon tank. A few examples would be ocellaris and mocha storm clownfish. 

20 gallons is only the starting point. Since small tanks are treacherous and difficult to manage than bigger ones, always opt for an upgrade whenever possible. 

Can You Have 2 Clownfish In A 20-Gallon Tank?

Yes, you can keep 2 small-sized clownfish, like perculas and ocellaris clownfish, in a 20-gallon tank – but only temporarily. 20 gallons is the bare minimum requirement for 1 clownfish, not 2.

I skimmed through a few threads and forums to find out the answer. And sorry, but nobody really recommends keeping more than 1 clownfish in a 20-gallon tank. 

How Many Clownfish In A 30-Gallon Tank? 

30 gallons is the minimum requirement for several different clownfish like perculas, maroons, cinnamons, and pink skunks. You can add just 1 of these fish to a 30-gallon tank. If you plan to add ocellaris clownfish, you can add a pair. 

Sadly, 30 gallons is not enough for bigger specimens like saddlebacks and blue-striped clownfish. 

How Many Clownfish In A 40-Gallon Tank? 

You can keep 1 saddleback clownfish in a 40-gallon tank. And if you want to raise species like percula, ocellaris, or pink skunk clownfish, you can grow a pair of them in a 40-gallon tank. 

How Many Clownfish In A 50-Gallon Tank?

50 gallons is the minimum requirement for a single Allard’s clownfish. However, you can keep 1 pair of percula, ocellaris, pink skunk, or tomato clownfish in a 50-gallon tank. 

How Many Clownfish In A 55-Gallon Tank? 

A 55-gallon tank is longer than a 50-gallon tank, but in terms of width, it’s smaller. So you can keep 1 Allard’s clownfish in a 55-gallon tank. And you can once again keep a pair of either percula, pink skunk, ocellaris, or tomato clownfish in a 55-gallon tank. 

How Many Clownfish In A 75-Gallon Tank?

You can keep 1 blue-striped or McCullochi clownfish in a 75-gallon tank. You can keep a pair if you plan to keep smaller species like perculas and pink skunks. 

No matter how big the tank is, it can seldom host more than 2 pairs at a time. 

Final Words: How Many Clownfish In A Tank? 

Clownfish are not exactly goofy and gullible, as portrayed in Finding Nemo. As a matter of fact, these fish can get quite mean and bully the opponent to the brink of death. They are naturally territorial and aggressive – some more than others. 

Therefore, I’d suggest keeping only a pair of clownfish in a single tank unless the tank in question is really very big or you have years and years of experience with overstocking clownfish. 

As you can also see from all the real answers shared above, the safest and the best way forward is keeping no more than 2 clownfish in a tank. 

Recommended Readings!

How Fast Do Clownfish Grow? Answers For Every Species!

How Many Gallons Does A Clownfish Need? Answers For All Species!

How Do Clownfish Sleep? Upside Down?

rohit gurung author at urbanfishkeeping

About Rohit Gurung

My never-ending love and fascination with Aquascaping started when I received a red-eared turtle for my 10th birthday.

Apart from researching and writing, I spend hours gazing at my 3 turtles. And yeah, I bask alongside them too.