How Big do Clownfish Get?

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Clownfish are probably the most notorious marine fish species and for good reasons. These fish are generally gentle, very colorful, and with tons of personality.

They are also a breeze to care for and can reach 10 years in good conditions.

But there are several types of clownfish available and they’re not all identical. The Nemo type is the most well-known, but other types are vastly different.

Some are more aggressive, more pretentious about their water conditions, and even differ greatly in terms of size.

Today, we will discuss the latter and look into the different clownfish breeds to assess their size and the factors influencing their growth rate. Let’s get into it!

Size of Different Clownfish Species

Clownfish Breed Adult Size Growth Rate
Common clownfish (Nemo) Up to 4-4.3 inches Up to 1 inch per year
Pink skunk clownfish Up to 4 inches Up to 1 inch per year
Saddleback clownfish Up to 4.5-4.7 inches Up to 1 inch per year
Tomato clownfish Up to 5-5.5 inches Up to 1 inch per year
Maroon clownfish Up to 5.5-6 inches Up to 1 inch per year
Cinnamon clownfish Up to 4.7-5 inches Up to 1 inch per year
Clarkii clownfish Up to 3.5-4 inches Up to 1 inch per year

These are just some of the clownfish breeds available, as there are 30 species you can choose from today.

These fish all differ in size, but their growth rate remains pretty much the same, between 0.5 to 1 inch per year.

Their growth rate varies based on genetic makeup, diet, environmental conditions, stress levels, etc.

Do Clownfish Get Bigger in the Ocean?

Interestingly enough, no, clownfish don’t get bigger in the ocean. Even if they do, it’s not by much.

The typical common clownfish won’t grow more than 4.3 inches, whether it’s in the ocean or captivity.

This is somewhat atypical, seeing how most fish are generally larger in their natural habitat compared to the aquarium.

How Fast do Clownfish Grow?

Most clownfish grow up to 1 inch per year, even in impeccable conditions. They can, however, experience slower growth, depending on the case, and that’s what we’ll be discussing next.

Factors that Affect Clownfish Size

There are several overarching factors that will influence the fish’s size, such as:

– Feeding and Diet

You want to provide all your clownfish with a healthy, omnivorous diet that would provide them with a complete pack of nutrients. Wild clownfish tend to prioritize meaty foods, but they accept a more omnivorous-oriented diet in captivity.

They even consume algae occasionally, along with live foods and commercial fish foods, depending on their preferences.

Frequency-wise, most adult clownfish are fine with one meal per day. However, this depends based on the fish’s size, age, water conditions, and even personality.

Juvenile clownfish require 2-3 small meals per day due to their more accelerated metabolic rates.

The best approach is to feed your clownfish a diet that would mimic its natural sustenance. Aim for foods higher in animal protein, such as copepods, anemone tentacles, fish eggs, brine shrimp, bloodworms, etc.

You can mix some algae pellets here, along with spirulina and various veggies, depending on your fish’s preferences.

Clownfish aren’t too pretentious about their meals, but different fish may prefer different treats.

– Tank Size

Unlike goldfish, clownfish don’t grow as much as their habitat allows them to. That being said, they can get stressed in small setups which will visibly hinder their growth.

You need at least 20 gallons for one adult clownfish, but you should consider a lot more space for a group. Especially since clownfish like to live in groups of at least 4-5 specimens.

Overcrowding clownfish or keeping them in small tanks can stress them out which weakens their immune system with potentially deadly consequences.

In the wild, clownfish live in hierarchical communities led by one dominant female a mating male, and several underdeveloped hermaphrodites.

It’s safe to say that they require a fair amount of space to remain comfortable and happy.

You also need to consider a larger tank to accommodate the layout itself. You need to add a reef structure, plants, various aquatic decorations, and maybe even anemones if you can handle them.

These shouldn’t occupy the entire tank, especially since clownfish also require plenty of swimming space.

– Sex

This is an interesting and unexpected point for people who are not aware of the clownfish’s physiology.

Clownfish are all born hermaphrodites with both male and female organs. These organs are immature, though, and will remain so in a group.

That’s because the most dominant clownfish in the group will change sex and become a female with the next in the hierarchical line turning into a male for breeding purposes.

The rest of the clownfish will become submissive and stop their growth until the female of the group dies or leaves the group. In such a setup, the dominant female will be the largest.

So, the fish’s sex matters when determining the individual’s size.

– Water Conditions

Sick clownfish stay smaller and experience a slower growth rate compared to healthy ones.

Clownfish are not particularly sensitive to disease, but they require a varied diet and stable environmental conditions to remain healthy. Otherwise, they will experience hindered growth and high levels of stress.

Water conditions are essential in determining your clownfish’s size and growth rate. Always have a good tank maintenance routine in place to prevent ammonia and nitrite buildup which will affect your fish’s wellbeing.

Also, invest in a water tester to check oxygen and nitrate levels. This allows you to know when a water change is necessary to refresh the environment.

Live plants are key in this sense, given that they consume nitrates and improve water oxygenation, but don’t overplant your aquarium.

Plants consume oxygen during nighttime and release CO2 which can lead to CO2 poisoning.

– Stress

Fish stress is a more common problem than people think. It is also difficult to detect if you’re not accustomed to your fish’s behavior.

Clownfish can experience stress for a variety of reasons, such as:

  • Improper diets or insufficient food
  • Not enough space, leading to overcrowding and territorial fights
  • Aggressive or overactive tankmates that can bully or attack your clownfish
  • Poor water conditions leading to skin parasites, difficulty breathing, or general discomfort
  • Loud noises or agitation in the aquarium room
  • Sickness, etc.

Another interesting point here is the improper group size. Never have 3 or 4 clownfish. You either get a pair or more than 6 preferably. This is all due to the clownfish’s social organization and how they operate in a community.

In short, clownfish live in large groups, but they only breed in pairs and you can only have one breeding pair per group.

The dominant pair consists of the largest male and female, while the rest of the clownfish remain as hermaphrodites, considerably smaller in size. If you have 3, 2 of the clownfish will pair up and begin to bully the 3rd one.

The same happens in a group of 4 clownfish, with 2 forming a pair and bullying the other 2.

The same bullying tactic occurs in larger groups as well, but at least you have multiple clownfish in the same community.

So, the bullying behavior will spread across all members; you won’t have 1 or 2 clownfish taking all the heat.

– Health

Always monitor your clownfish for health issues, even if they seem healthy at a first glance.

Clownfish aren’t known as sensitive fish, but they too can experience health problems occasionally.

These are most often the result of poor feeding, improper water conditions, stress, contaminated water due to improper water changes, etc.

Even sudden temperature shifts can cause fish stress, affecting the clownfish’s immune system.

The most widespread marine diseases to look out for include:

  • Marine Ich
  • Velvet disease
  • Brooklynella (the clownfish disease)
  • Uroenma disease (parasitic)
  • Flukes
  • Bacterial infections, and many others

This isn’t to say that clownfish are extremely sensitive to health issues, but they’re not impervious to them either.

These fish need a healthy habitat, stable water parameters, good food, and a stress-free lifestyle to remain healthy over the years.

For this reason, you should always assess your fish’s behavior and overall condition once you learn its temperament. Drastic temperamental changes should stand out immediately.

Some abnormal behaviors include lethargy, lack of appetite, erratic swimming, gasping for air, etc.

If you notice these signs, check your fish more closely to detect other symptoms that may hint at the condition it’s dealing with.

Quarantine is then necessary to contain the problem until you figure out the right approach.


Clownfish rank as moderately-sized fish with a lot of variation in size, depending on the breed.

Even so, they won’t grow too far apart, as all species remain in the 3-6-inch range.

So, always choose your clownfish species carefully, especially since you will keep these fish in larger communities in need of proper tank space.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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