Ultimate Guide to Clownfish, what are their habits?

Made famous by the blockbuster movie, Finding Nemo, clownfish are small fish, orange in color with white stripes outlined in black. They usually reside in a sea anemone, and if you spot one, you will most likely find its family nearby!

How Big is a Clownfish?

Clownfish are relatively small fish. An adult clownfish is on average around 3 inches (88 millimeters) long. But they may grow to around 4 inches (110 mm). Females are larger than male clownfish, with the juveniles varying in smaller sizes according to their age.

Read More: Other Incredible and Fun Marine Facts

Why are Clownfish called Clownfish?

Clownfish are actually known by the name, Amphiprion ocellaris in the scientific community. They can also be called Common clownfish or a False clown anemonefish. So where does the clownfish name come from?

Clownfish get their slang name from the bright and bold colored strokes painted across their bodies, which resembles a clown’s face paint.

And how did Nemo from the movie, get his name?

From his anemone home, a-NEMO-ne!

Do Clownfish Change Genders?

Clownfish can change genders. They are born hermaphrodites, meaning that they are born with both sex organs. Clownfish will develop first into males and then into a female if the need arises.

A clownfish family will usually consist of an adult female, an adult male, and several juveniles. When the female is removed or dies, the adult male will change genders to become female and the dominant clownfish. The largest juvenile will then step up and transform into the adult male.

The female keeps her place by dominating the male, preventing more female clownfish. While the male dominates the juveniles to prevent any reproduction between them and the female.

What is the Relationship Between a Clownfish and Sea Anemones?

Sea anemones are closely related to coral and jellyfish. They are considered marine animals as they have the ability to protect themselves using their stinging tentacles. The anemones spend their lives attached to the bottom of the sea or attached to rocks waiting for food to drift past and get caught in their tentacles.

Clownfish and other anemonefish, have evolved to develop a symbiotic relationship with the sea anemones. The clownfish depends on the sea anemone for protection and shelter; as clownfish are small, slow swimmers and easy prey. Clownfish also use anemones as protection for their nests and nibble on the anemone’s leftover food.

Anemone with their host family, clownfish
Anemone with their host family

The sea anemone, however, uses the clownfish family to remain healthy. Anemones have been observed to thrive better with a host fish, as the clownfish keeps the anemone’s tentacles clean and free from parasites. They also drive away any butterflyfish who are looking for a tasty anemone meal. It is also thought that with the fish swimming around, and constantly fanning their fins, there is increased water flow which brings oxygen and nutrients to the anemone.

So how do the clownfish protect themselves from the sea anemone’s painful and stinging cells?

The clownfish first needs to acclimatize themselves to the stinging cells to become immune. This process involves the clownfish rubbing its body on the ends of the anemone’s tentacles to create a protective mucus layer!

How do Clownfish Reproduce?

The adult male clownfish will first prepare the nest area. This is usually below or under the anemone where the tentacles can still offer protection from predators.

The male will attract the female by extending fins, biting, chasing, and driving the female to the nest. The female will then swim over the nest a few times before laying her eggs. The male will then pass over the eggs to fertilize them.

How many Eggs do Clownfish lay?

Depending on the age of the clownfish, females can lay between 100-1,000 during one cycle. It takes about 1-2 hours for her to lay her eggs, then 6-8 days for the eggs to incubate. It has been observed that the colder the water, the longer it takes for the eggs to spawn. Once spawned, the clownfish are at the planktonic larval stage which will range from 8-12 days before becoming juvenile fish that needs to find an anemone to inhabit.

Emma was initially terrified of the deep ocean but dived right into scuba diving years ago and hasn't looked back since! After completing her PADI DiveMaster certification and with a Bachelor of Communications (Media) background in film-making, Emma started her scuba career as an Underwater Videographer before becoming a full-time PADI Master Scuba Diver Trainer. She taught and certified hundreds of PADI scuba divers as Open Water Divers, Rescue Divers, Deep Specialty Divers, Dive Masters and more, and then managed several Dive Centres. Her favourite fish (which is also tattooed on her arm) is the Barracuda!