Reasons Why Clownfish Turn Black + Why They Get Black Spots

Reasons Why Clownfish Turn Black + Why They Get Black Spots

Clownfish about to turn black

Aquarists often buy clownfish for their vibrant coloration and distinct patterns.

However, over the due course, they observe their clownfish turning black.

So, why do they turn black?

Main Reasons Why Clownfish Turn Black

Clownfish are the preferred choice of aquarists for a community aquarium or reef tank.

However, these bright-colored fish can turn black over time, even after providing the best living conditions.

The color change in clownfish takes place mainly due to the following reasons.


Aging is one of the primary reasons for clownfish to turn black.

Many clownfish species are notorious for getting darker as they age.

Black Ocellaris, Onyx, and Maine Mocha clownfish are among the numerous species that turn black as they grow old.

These clownfish species don’t turn black outright. Their color darkens slowly and becomes more pronounced with age.

Gender Change

Another reason for clownfish to turn black is gender transformation. Clownfish are protandrous hermaphrodites.

All clownfish are born as males.

When the female in the group is no more, the dominant male switches gender to become a female for reproductive purposes.

Clownfish have male and female reproductive organs that help them turn into females when needed.

Most clownfish species become darker when they change their gender and use their female reproductive organs.

As they turn into a darker shade than usual, they appear black.

Should You Be Worried if Your Clownfish Is Turning Black?

Some clownfish species are known to get dark and turn black as they age.

There are certain physical changes that clownfish undergo as they grow old. Turning black is an indication that they’re aging.

So there is nothing to worry about if a color change is the only noticeable difference as your clownfish gets old.

However, if you notice a behavioral change after your clownfish turns black, it needs immediate attention.

You need to consult a veterinarian for expert advice if you notice any unusual behavior in your clownfish, such as erratic swimming, not eating, or hiding under rocks.

Reasons Why Clownfish Get Black Spots

It’s common for clownfish to turn dark and appear black as they age.

However, you may notice black spots on your clownfish at a young age.

Given below are the prominent reasons for clownfish to get black spots.

Coral Exposure

Coral in aquarium

The most common reason why clownfish get black spots is coral exposure.

In the wild, clownfish and anemones form a symbiotic relationship where anemone host clownfish.

Clownfish depend heavily on anemones for survival.

However, in captivity, anemones aren’t necessary for clownfish as there is no fear of predation.

Hence, most aquarists house clownfish in a reef tank without anemones.

In such cases, clownfish are forced to seek refuge inside the coral in the tank.

They usually don’t reside inside the coral in the wild. So it affects them negatively.

Clownfish expose their skin to the corals to build up the mucus layer on their skin’s surface.

However, when clownfish expose their skin, the corals sting them, leading to black spots on the skin.

Researchers have found that exposure to corals causes hypermineralization in the bodies of clownfish.

Repeated exposure to corals leads to repeated stings, which leads to black pigments all over their body.

Although corals sting clownfish and cause black spots, the black spots aren’t fatal to clownfish.

Neither do they cause any behavioral change in them.

Poor Water Conditions

Poor water quality is another reason for black spots on clownfish.

Clownfish are sensitive to water conditions and need clean water to thrive.

The tank water can get polluted due to poor filtration systems, high ammonia levels, nitrates, and other contaminants.

These pollutants affect the health of clownfish and lead to black spots.

As these pollutants accumulate in the aquarium, they eventually affect the skin of clownfish. This leads to black spots on their skin.

Any parasitic or bacterial infection can also be one of the causes of black spots on your clownfish.

Hence, if you notice significant black spots on your clownfish, change the tank water immediately to prevent asphyxiation of your fish.

Black spots due to poor water conditions shouldn’t be ignored as they can cost your fish its life.

Do All Clownfish Become Dark as They Age?

Not all clownfish species darken as they age. There are over 30 clownfish species, each with a different appearance.

Some of them don’t turn black at all.

The species of clownfish determines whether they will turn dark with age or not.

For example, Black Ocellaris clownfish turn dark as they grow old.

These clownfish are orange while young and turn black as they mature.

Another species that is popular for turning dark over time is the Onyx clownfish, commonly known as Percula clownfish.

Onyx clownfish have a dark pigment that gradually manifests as the fish ages.

You may not see this until the fish reaches adulthood.

This is because the pigment takes some time to develop.

Onyx clownfish become dark in the middle of their body, while their head and tail retain the original orange color.

Another example is Maine Mocha clownfish. This fish is unique for its varied coloration and patterns.

These fish also turn dark as they mature. Some of them turn entirely black, with the nose retaining its orange-brown color.

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