My Big Ocellaris acting different

[409corey]

My boyfriend is at work and took over his name so I can get some questions answered.. We bought a baby Ocellaris Clown fish to add to our tank and then later bought a bigger Ocellaris. They have gotten along great,but all of the sudden our Big one seems to be nipping and nudging our little one. Any thoughts of why this might be happening? Big one is like two time bigger!

 

[garygb]

The larger fish may be reaching sexual maturity and is almost certainly a female at this point. Aggressive behavior is typical for female clowns, and the smaller fish (male) will likely shake to show submission. In case you're new to clownfish, when they hatch they are all juvenile males. As time goes on the larger fish become female and the smaller ones remain male. In the wild, several clownfish can often be found in the same anemone. In this case there's the male and female pair and several "intermediate" males that will remain somewhat smaller than the breeding pair. If something happens to the breeding female, the breeding male will become female and one of the intermediate males will assume the breeding male's position. Clownfish aren't the only fish that change gender.