Clownfish are one of the most well-known tropical fish. But even though we see them on our TV screens, what do you know about them in real life? They live in social groups in which individuals are ranked by size (size-based dominance hierarchy). The two biggest dominant individuals breed (have babies), but the smaller individuals do not. So why do some clownfish forgo their own reproduction?
We decided to investigate the smaller clownfish. We looked at the risks and rewards of moving to a different home to breed or of contesting to breed in their current home. We found that it’s too risky for these clownfish to move to a new home. Furthermore, they aren’t likely to contest by getting bigger and potentially fight the dominants since they risk being evicted from the group. So, they choose to stay put and wait in the hope that they will one day be able to breed.