The Saddleback Clownfish

Marine life around Koh Tao - Clownfish

Saddleback Clownfish Saddleback Clownfish (Amphiprion polymnus) is common to the dive sites of Koh Tao, with this fish (made popular by the 2003 computer animated comedy drama) having made his home at the popular dive sites of Twin Peaks and Crystal Dive’s own house reef, Junkyard.

This cute little guy is a favourite for all of our divers who venture over to ‘Turtle Island’ to scuba dive, whether experienced or those taking their first discovery dive.

Saddleback Clownfish are usually found living on a sandy patch on the bottom, away from the main coral reef at a shallow depth.

Here you will see them moving in and out of their “house” – a sea anemone – and they live on a diet of zooplankton and algae.

Meet The Family

The Saddleback is part of the larger Pomacentride family which includes Clownfish and Damsel fish. Many of these fish are brightly coloured and defensive of their territory.

Inside their host Anemone the clownfish will colonize their home and create a hierarchy system, with the largest and most aggressive female sitting at the top. Only the dominant male and female will be able to reproduce, with clownfish usually spawning around the time of the full moon.

Circle Of Life

Nearly all clownfish will alternate between sexes at some point in their life. All are originally born as males with the change occurring when they mature. To keep the colony alive once the dominant female is removed, usually by death, one of the largest males will develop into a female with all the other males then moving up the hierarchy.

Most clownfish have a life span of around 10 years in the wild while if kept in captivity they can live for to 18 years.

My House Is My Castle

These bottom dwelling fish are notorious for being territorial and defensive of their home keeping away any would be trespassers. When scuba diving if you get to close to “Nemo” he may come up and give your mask a little nip. Here on Koh Tao we take marine conservation very seriously.

One of most popular dive sites on Koh Tao is Twin Peaks and conservation minded divers have built an exclusion zone several metres in diameter around Nemo and his home.

Nemo is a very popular guy especially for divers completing their open water courses. Instructors will take their students over to see him, but all divers remain outside the exclusion zone. You can watch Nemo as he dances in and out of his anemone, but by giving him just a little space we reduce the risk of him hurting himself while trying to “attack” a diver!


Clownfish and sea anemones have a unique symbiotic relationship with each other, with each providing benefits for the other. The sea anemone tentacles are poisonous to touch for most marine organisms but the clownfish have evolved so they are not affected by the poison.

This allows them to use the anemone as their home. While the clownfish will defend the anemone from any predators and parasites and at the same time provide food, as the anemone will eat any leftover scraps from the clownfish’s food.

Learn More

This is just one of the many symbiotic relationships that we experience here on Koh Tao. If you wish to learn more on this subject why not consider enrolling on the PADI Underwater Naturalist Specialty course.

Author: Neil Davidson (PADI MSDT #294100)

Crystal Dive Koh Tao

7/1 Moo 2
Tambon Ko Tao
Koh Tao
Surat Thani


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