Ocellaris Clownfish Care

The Common Clownfish is an easily recognized fish, and it’s been one of the most common in the hobby for some time. Even those who weren’t interested in keeping them know some of the basics thanks to pop culture, from the fact that they dwell in anemones to their colorful appearance.

While they’re not the easiest fish to keep, they’re not too hard for a careful beginner either. Read on and we’ll dive into the wide world of caring for the Ocellaris Clownfish.

Ocellaris Clownfish


Ocellaris Clownfish Quick Care Sheet

  • Common Name: Ocellaris Clownfish
  • Alternate Common Name(s): Common Clownfish, False Percula Clownfish, Nemo Fish
  • Latin Name: Amphiprion ocellaris
  • Care Level: Moderate
  • Tank Size: 10+ Gallons
  • Size: 4”
  • Diet: Omnivorous
  • Behavior: Semi-aggressive
  • Lifespan: 15+ years
  • Reproduction Type: Egg Layer
  • Water Temperature: 75–80°F (24–27°C)
  • Salinity: 1.020 – 1.024
  • pH: 8.0-8.4

Origins of the Ocellaris Clownfish

Native to Australia and Southeastern Japan, the Ocellaris Clownfish is a frequent sight along reefs. While the most seen specimens are orange (and not to be confused with the Orange Clownfish, Amphiprion percula) they range from yellow to dark red depending on the morph. They also display different series of stripes depending on the exact color morph that they’ve been bred into.

The Ocellaris Clownfish is a smaller reef fish, coming in at only 4” at maximum. Specimens on the upper end of that range will tend to be females, or rather the female of the group.

In the wild Ocellaris Clownfish form small groups. In these groups, the highest fish in the pecking order will be the female while she breeds with just one male. The other males are functionally sterile, unable to partake in even opportunistic breeding.

It gets weirder.

If the female dies or becomes lost, the males in the group will contest to see who’s highest on the pecking order. That one in turn releases hormones that cause it to become a fertile female while another one of the males takes the place as her mate. Often the previous mate will be the new female.

The Ocellaris Clownfish is the most popular breed currently, the movie Finding Nemo thrust the species into the spotlight. I’ve even heard them referred to as “Nemo fish” a few times.

Clownfish are also known for their symbiotic relationship with anemones. They’re immune to the tentacles and hide among “their” anemone to keep away predators.

This is a symbiotic relationship, where both of the organisms will benefit from the arrangement. The clownfish get shelter, and the anemone gets a clean-up crew and something that lures prey in.

In the absence of an anemone, clownfish will sometimes seek the same arrangement with certain corals. Hammer and frogspawn corals are among the known varieties that clownfish will use.

These fish are rather tolerant of conditions for saltwater fish, but still require more care than an “easy” freshwater fish. They’re a great choice for those starting in the hobby, but I’d recommend placing them in a tank that’s at least 20 gallons to start with for a more stable system overall.

Ideal Tank Setup

Standard reef tank chemistry is fine for these fish, and they can tolerate conditions a bit out of their listed parameters for some periods of time.

That said, there are a few extra things you can do to help the fish thrive in captive conditions.

Low Current

These fish live in relatively still lagoons and tend to only be 10-15 meters under the surface of the water. They’re not very tolerant of high currents and they’ll get bashed about if you’re not careful.

Low flow will result in happier clownfish, but you’ll need to balance that with your tank’s filtration needs as well. Just be aware that you may have to take alternate strategies to filtration if you need more.

The problem is simple enough: Ocellaris Clownfish aren’t great swimmers. Adjust the flow of the filters downward if you notice they’re having trouble.

Hiding Spots

Most specimens of this species are fine with not having an anemone to bond with.

They do need hiding spots, however, as these fish are rarely out in the open with nowhere to retreat. Try creating small caves with rocks or other decorations to give them their own little home.

It’s fairly basic, but it’s very important for these fish to have somewhere to retreat. Much of their natural life is spent darting in and out of their anemone cover in the wild, and you want to at least approximate the same experience. 

Are Clownfish Reef Safe?

Some fish that naturally live on the reefs don’t do well as captive fish. They may eat coral skeletons, have too much of an appetite for an enclosed space, or even be dangerous to other fish and invertebrates in the tank.

Clownfish are an excellent choice to introduce to most reef tanks. We’ll go over some of the issues in the next section, but as a general rule, you won’t have any trouble with the vast majority of normally kept reef fish, critters, and corals.

If your Ocellaris decides to bond with a coral you may have a minor problem. Sometimes the polyps will become irritated and retract, pushing the coral into a declining state. This is very uncommon, but something to keep an eye out for if you introduce them into an established reef tank.

What About an Anenome?

Anemones are great, and they form a natural habitat for your clown fish that matches their wild environment. It makes them feel secure, gives them actual defense if you misjudge some of your fauna’s aggression, and they look great.

The Ocellaris clownfish is known to form a symbiotic relationship with the following types of anemone:

  • Magnificent Sea Anemone (H. magnifica)
  • Giant Carpet Sea Anemone (S. gigantea)
  • Merten’s Carpet Sea Anemone (S. mertensii)
  • Bubble Tip Anemone (E. quadricolor)

The Bubble Tip Anenome is a maybe. Most Ocellaris Clownfish will readily adapt to it, but rare specimens won’t. It’s even less of a problem if you make sure to get a captive-bred Ocellaris instead of a wild-caught specimen.

If you’re new to dealing with marine fauna, you can be forgiven for thinking an anemone is something you can just plop into the tank. They may seem more like plants at first glance… but anemones are mobile, hard to keep, and often aggressive.

That poses a problem for the new aquarist, especially if you’re adding the anemone to an established tank.

Oh, and your Ocellaris Clownfish?

They’ll be happy, but they’ll also aggressively defend their new anemone once they make it home. This can change the entire dynamic in a tank.

It’s better to think of it as adding a Clownfish for your anemone instead of adding an anemone for your fish. The anemone’s pristine, balanced water requirements are much harder to maintain than those required by the fish.

You also have to be aware of which kinds of fish and invertebrates that any given anemone will eat.

There’s one other issue: anemones aren’t propagated and sold very often. There are a lot of wild-caught specimens on the market, and the sad truth is that the majority will end up dying before they multiply.

But here’s the thing: Ocellaris Clownfish will also bond with some LPS corals like Hammer Coral and Frogbit Coral. These are easier to care for, less aggressive, and less mobile. They’re also commonly propagated in captivity and easily found.

It’s up to you, but you need to remember that sea anemones are hard to keep. Clownfish, on the other hand, are robust for marine fish. If you just want a tank with a Nemo look-alike then skip the anemone and save yourself the headache. 

Clownfish Behavior

Clownfish form a rigid hierarchy when there are multiple specimens. The groups are led by the largest, most aggressive fish which is a female. If the female is lost, the dominant male becomes female and the pecking order cycle continues.

While fascinating, it can also cause some behavior that will raise an eyebrow.

The female will always bully the male and those lower in the hierarchy. It’s just the way things go. The male will usually submit by turning to the side, telling the female it’s had enough.

The Ocellaris Clownfish is a cute little fish, which is what draws people to them.

That said, they’re surprisingly territorial and a bit on the aggressive side. They’re usually considered semi-aggressive, with other fish. In-group fights are going to happen on a regular basis, but they’re nothing to be worried about unless the smallest fish in the pecking order is beginning to look sick or hurt.

This in-group aggression actually makes it hard for a baby clownfish to find a home in the wild, but they’ve managed for a few millennia this way. 

Get used to a bit of bullying or only keep one clownfish per tank.

Breeding Ocellaris Clownfish

Breeding these fish is actually fairly easy. You can grab two Ocellaris and throw them together, let them sort out who’s the dominant fish, and that one becomes the female.

Keep in mind that you can only breed a single pair per tank realistically unless we’re talking massive enclosures. The group of fish always has only one breeding pair, the rest of the fish in the tank will remain essentially sexless unless something changes the group dynamic.

The pair will mate occasionally as long as they’re kept in a clean tank. Keep an eye out for eggs near their hiding spot, whether it’s an anemone, coral, or just a rock cave. The eggs are small, round, and orange before the fish begin to develop.

Clownfish will eat their fry, and occasionally their eggs. You should remove the fry as soon as they’re free-swimming. You can move the eggs to the grow-out tank as well, but it’s usually easier to just move the fry once they’re swimming.

Get a fine net, they’re tiny.

There will be a ton of fry. Clownfish lay between 400-1000 eggs.

Most of them won’t make it, but that’s just the nature of massive reproduction. In the wild, the Ocellaris Clownfish has about a 1% chance of survival. Researchers have managed a 90% survival rate with everything they need. Your tank is likely to be in the middle, which is still a lot of clownfish.

You’ll need a fully cycled grow-out tank which is around 10 gallons. 

If you can manage it, a small tank with a sump that’s 100-200% of the actual tank size will make water parameters more stable and may reduce the need for water changes.

After a few weeks, the fry will transition into being juvenile fish. You can tell this is happening when they begin to get some color to them.

Due to the large number of fish you’ll end up with I would suggest figuring out what to do with them before you start breeding. You may be able to sell them to an LFS, or talk to people on fishkeeping forums and social media groups to see if they’re interested.

That said, it’s a rewarding experience. Marine fish are usually much harder to breed in captivity, but even amateurs have enjoyed success breeding the Ocellaris.

Raising Nemo

The Ocellaris Clownfish is a popular marine aquarium fish for good reason: they’re easy to keep, they have interesting behavior, and they’re attractive. They’re even easy to breed at home! These fish are an iconic bit of reef fauna that you can’t ignore. Just be aware that keeping them in a symbiotic relationship with an anemone complicates things quite a bit.

On the other hand? It’s hard to get over the joy of watching these orange fish go about their daily lives.