Thanks to Disney, everyone knows arguably the worlds most famous fish: Nemo , and the clownfish's interesting relationship with the Sea Anemone . However, not everyone knows all of the interesting things about young clownfish. Young clownfish including Percula, Ocellaris or "False," Maroon, Tomato and others have not yet chosen a gender. As they grow and mature, a group of clownfish will form a "pod," which is kind of like a family!
Each Pod may have between 2 and 6 fish, and within the pod a dominance or "pecking order" will be established. The largest and most aggressive fish will grow into the female, the 2nd largest will become the male, and the rest will all stay juvenile "sub adults." If anything ever happens to the male, the next largest fish will mature and take his place.
Now here is the interesting part. If the female leaves the pod, the male will then be the largest and most dominant. He will then grow and become female. The next largest fish will take his place as the new male.
Clownfish are by far the most loved and common of all saltwater aquarium fish, and for good reason! They have bright colors, interesting personalities and nearly all those available in the trade are tank raised. This is important because it reduces the impact on natural reefs, and produces fish that are healthy and accustomed to life in captivity. But the #1 reason clowns are so popular is that they form a symbiotic bond with Anemones !
Watching your clowns frolic in their anemone is one of the greatest joys of having a reef tank. Just keep in mind, your baby clowns have never seen an anemone in their lives and it may take them some time to get used to the idea.