Are Clownfish Aggressive? Will They Bite Your Finger?

Feb 18, 2022

Are Clownfish Aggressive

No fish – real or animated – has captured our hearts like Nemo has. The naivety and cuteness that define Disney’s animated fish got us all thinking that clownfish have a similar temperament in real life too. 

But the saying, “Don’t judge a book by its cover,” couldn’t be any more accurate in a clownfish’s case. 

Do you know clownfish are feisty and sassy in reality?

Are clownfish aggressive? Yes, they definitely are. 

Do they eat other clownfish? And bite humans? Keep reading, and you will know! 

Are Clownfish Aggressive?

Yes, clownfish are aggressive. Don’t go by size. These fish pack a lot of personalities. They are aggressive and territorial fish that don’t mind engaging in duels and fights every now and then.

Unfortunately, the aggression in clownfish is an innate behavior. They’re hardwired to be mean. 

That’s because these fish are native to the coral reefs in the wild, and anyone who knows the ocean knows that coral reefs are no place for the faint-hearted. 

Coral reefs serve as both shelter and hunting grounds for the fish. It’s a highly competitive part of the ocean to live in as opportunistic predators are lurking by at any given moment. 

Any fish that lives in the coral reefs must have an assertive personality to ensure survival. And this is precisely the reason why clownfish are so aggressive. 

As you can guess, their aggression translates in tanks, too – irrespective of whether they were caught in the wild or born and bred in captivity. 

If you’re a beginner fishkeeper, a teeny tiny clownfish holds power to keep you on your toes all the time due to its anger problem.

However, once you get to know it and its needs better, you can manage the anger for the most part. 

Below, I will list a few reasons that trigger violence and malice in clownfish in a tank. 

Related Reading: Clownfish Lifespan | How Old Is The Oldest Clownfish?

5 Reasons Clownfish Are Acting Aggressive In The Tank 

Clownfish are intrinsically aggressive fish. Therefore, they don’t really need that big of a reason to act mad. Common aquarium problems like territorial aggression, wrong tank mates, a poor tank setup, and improper diet can cause them to blow a fuse every now and then. 

Let’s dissect these reasons in detail below! 

Your Clownfish Is A Wild Specimen 

Most clownfish that we know and love are born and raised in captivity. So, it’s unlikely that the one you have is a wild specimen. 

But we cannot still entirely rule out the possibility. 

And frankly, I wouldn’t blame a wild clownfish for being angry and frustrated in an aquarium? I mean, who wouldn’t be, right?

Wild-born clownfish are naturally more inclined to become territorial than their captive-bred cousins. After all, they used to have an entire frigging ocean to call home, for god’s sake! 

And since they’re used to defend themselves against constant threats that lurk in the ocean, they’re obviously more alert, suspicious, and intolerant of any other presence in the tank. 

Clownfish Is Just Defending Its Home (Anemones)

Clownfish and anemones share one of the most winsome interspecies relationships known to men.

Anemones provide shelter against deadly predators and food scraps to clownfish. And in return, clownfish offer essential nutrients in the form of poop and often act as bait to lure prey. 

So, if you have anemones in the tank, it’s only natural that the clownfish will assume it to be its home and defend it at any cost. 

While anemones come equipped with poisonous stingers that pack a good punch to anyone that comes close, clownfish have adapted to produce mucus that prevents them from being stung. 

So, if you plan to add anemones to your clownfish tank, you need to gauge the size and location of these long tubules strategically. 

You Chose The Wrong Tankmates 

By now, we have clearly established that clownfish are territorial and aggressive creatures. 

And if they’re kept in an environment where they feel vulnerable to attacks at all times, they’re, of course, going to act on it. 

The subsequent bullying and duels can even prove fatal in most cases. 

As the saying goes, an eye for an eye will only make the world go blind. 

Therefore, you should steer clear of aggressive and large fish like lionfish and groupers while selecting tankmates for your clownfish. 

Your Tank Is Poorly Set Up

Here’s what a tank setup for clownfish should look like:

  • Minimum tank size: 20 gallons 
  • Lighting: Moderate 
  • Water Movement: Moderate 
  • Temperature: 73-80 degrees F
  • pH: 8.0-8.4
  • Specific Gravity: 29 to 35 PPT (1.021-1.026)
  • Ammonia: 0 PPM
  • Nitrate: 0.2 PPM
  • Nitrite: 0.2 PPM 

While it’s not possible to emulate their original habitat by any measure, the least we can do as fish parents is provide vast space and maintain correct and stable water parameters at all times. 

If the tank is poorly set up, the water parameters are haywire and even worse, there’s not enough room to swim in, the fish will naturally become agitated. 

And anger should be the least of your concerns at this point. That’s because you’re putting your fish at immediate risk of contracting diseases. 

You’re Not Feeding Clownfish The Right Way 

There’s no cardinal rule to tell the right or wrong way of feeding clownfish. But the general practice in the hobby is giving 1 big meal or 2 smaller meals every day. 

If you’re feeding the wrong or too little food, this will sufficiently annoy the fish, who will then once again resort to anger to channel all that frustration. 

Before you know it, the feeding session will turn into mayhem – characterized by charging, chasing, shuddering, and even biting. 

Even you can get your fingers bitten! 

Those at the top of the pecking order will go away with the lion’s share, while those at the bottom can be forced to crouch and starve in the corner for days. 

How To Reduce Clownfish Aggression? 

clownfish aggression

Luckily, there are certain things you can do to profoundly lower a clownfish’s aggression. 

There are no tricks up my sleeves – these are all tried and tested methods like choosing the suitable tankmates, creating the right environment, providing ample space, keeping them in pairs, and so on and so forth. 

Let’s look at them one by one. 

Get A Captive-Bred Clownfish 

First things first – nipping the aggression in the bud. We have already discussed why wild-caught specimens are grumpier than their captive cousins. 

So, when you opt for a captive-bred clownfish, you’ll be doing all parties – you, captive fish, and wild fish – a favor. 

It’s hard to curb aggression when you confine a creature used to the oceans to a mere 4-walled tank. 

Your safest bet here would be to buy a specimen born and bred in captivity. 

Provide Ample Space 

Once again, don’t go by the size. These fish may look small, but boy, do they need a big tank. 

Thanks to their highly territorial disposition, you will need to provide a big tank adorned with multiple hiding spaces for clownfish. 

Although clownfish rarely grow any longer than 5 inches, they need at least 20 gallons of space per fish. 

If you are a beginner, I’d suggest against keeping multiple clownfish. 

And for those who plan to do so, you need to guarantee the tank’s big enough for these little fish to claim their tiny territories and prevent unsolicited confrontations. 

Lastly, if you plan to house anemones as well, you’ll need an even bigger tank. 

Related: What’s The Ideal Clownfish Tank Size? 5, 10 Or 20 Gallons?

Pick The Right Tankmates 

Picking the right tankmates for your clownfish can be pretty tricky. You don’t want to keep anyone big enough to hurt and gobble up your clownfish. 

Also, you definitely don’t want to keep anyone small enough for your clownfish to ruthlessly pick on. 

While choosing tankmates for your clownfish, don’t forget to weigh in factors like the fish’s size, temperament, and so on. 

And remember, clownfish don’t like to live with their own kind. 

The best clownfish tank mates would be:

  • Tangs 
  • Damselfish 
  • Puffers 
  • Blennies 
  • Angelfish 
  • Gobies 
  • Dartfish 
  • Hermit Crabs 
  • Blood Red Fire Shrimp
  • Basslets 

Keep Clownfish In Pairs 

If you intend to keep more than one clownfish, you need to ensure you keep them in pairs. This will help to mitigate aggression to a great extent. 

Since clownfish mate for life, keeping one male and one female fish would be your best bet. If you keep a pair and a singleton, the duo will pick on the lonely fish until it drops dead. 

Keeping multiple pairs can also lead to violent outcomes and bloodbaths – not even exaggerating – if there’s not enough space for everyone. 

In this case, you’ll need to invest in a huge tank and place the decors strategically to break the line of sight. 

Get The Tank’s Parameters Right 

We have already discussed above what the ideal parameters should look like for these fish. 

Anyone would feel stressed and hence angry when forced to live in the wrong conditions. And your clownfish is no exception. 

A clownfish that feels relaxed and safe is much less likely to be angry than one that’s under stress.

These fish need warm, saline water. The pH should clock in somewhere between 8.0 to 8.4. And both lighting and water movement should be set at moderate. 

And lastly, remember – fishkeeping is something like parenting. You have to work on it every day. 

Make it a priority to practice good husbandry practices like removing the uneaten food right away, performing frequent water changes, and testing the parameters regularly.

Here’s a link to API’s Saltwater Master Kit that monitors the 4 most crucial parameters in saltwater tanks: ammonia, nitrite, nitrate, and high-range pH. 

Feed The Right Food 

While shaping a dietary regime for your clownfish, it’s essential to look into their original feeding habits and choices first. 

They primarily snack on small invertebrates, algae, and fish scraps left behind by anemones in the wild. 

As omnivores, in the tank, they will readily accept most kinds of foods, from pellets to blanched veggies. 

Ensure the fish is well fed, so it doesn’t become hangry. 

My vet friend suggested that breaking one big meal into smaller meals will help curb resource-related aggression to an extent. 

And as it goes without saying, don’t forget to disperse the food equally in all parts of the tank so that everyone can eat without huddling at one spot.

Related Article: How Often To Feed Clownfish? Risks Of Underfeeding!

Frequently Asked Questions 

Now, before we end this article, let’s have a look at some of the most frequently asked questions. 

Why Is My Clownfish Aggressive To New Fish?

By now, you are well-versed that clownfish have a territorial temperament. So they will naturally act up when a new fish is being introduced to their tank. It’s perfectly expected behavior. 

Therefore, don’t forget to watch for signs of bullying and harassment towards the new member. 

And unfortunately, if you come to a conclusion that they can’t cohabitate together, you’ll have to rehabilitate one of them.

Why Is My Clownfish Attacking Another Clownfish?

Clownfish don’t really get along with others from their own species. It probably has something to do with the hierarchy, pecking order, social rank, and so on. Only they know the real reason. 

If you find your clownfish attacking other clownfish, you need to ensure there’s plenty of space for both parties to exist without confrontations. 

Also, don’t forget to add plenty of hideouts placed strategically so the bullied fish can retreat and catch a breath. 

Do Clownfish Attack Humans? 

Yes, clownfish can also ‘attack’ humans. For example, they are often known to bite fingers when feeding. Sometimes, it’s an accident – other times, vengeance! 

Thus, it’s best to drop the idea of hand-feeding your clownfish. 

Do Clownfish Eat Other Fish? 

Yes, clownfish will readily eat other fish if the opportunity strikes. They have been doing so in the wild for eons and will continue to do so in the tank as well. 

Are Clownfish Cannibals?

Yes, clownfish are cannibals. But, don’t be surprised – most fish are. After all, it’s a dog-eat-dog world, isn’t it?

What’s A Clownfish’s Behavior And Characteristics Like?

Clownfish are semi-aggressive fish, although their appearance says otherwise. They are pretty territorial, especially when defending their beloved anemones. 

Clownfish and anemones boast of one of the most endearing interspecies friendships. 

In the tank, clownfish should be housed with similarly-sized tank mates that can hold their own when the need arises. 

And in tanks that don’t have anemones, clownfish often assume a shell or a hollowed-out coral as its pseudo-anemone and stay close to it. How adorable! 🙂

Final Words: Are Clownfish Aggressive?

Are clownfish aggressive? Yes, they are. They are semi-aggressive fish. And they’re pretty territorial. They’re nothing like the gullible and goofy clownfish portrayed in Finding Nemo. 

The most likely reason behind a clownfish’s aggression is the lack of enough space to claim and swim around in the tank. Also, they get incredibly defensive when defending their eggs or anemone. 

Providing ample space, the correct parameters, amicable tankmates, and a well-rounded diet go a long way in curbing a clownfish’s anger problem. 

Related Articles:

White Spots On Clownfish! Copper-Free Treatment?

Can Clownfish Change Gender? How Many Times?

What Do Clownfish Eggs Look Like? Sushi Roe? Picture Guide

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.