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I bought 2 clownfish but they look like they are attacking each other for a few seconds. Then they stop then after a few minutes start again. Is that normal?
And secondly one of them has like another fin from the middle of the stomach. (pictures attached). That wasn't there when I bought it can anyone tell me what this is as well.

Many thanks



Staff member
Are these both oscelaris Clowns?
if they are the same species I can think of tow scenarios.
1) they are both female. In this case one will eventually kill the other.
2) only one is female or both are male. In this situation one will become dominant the other will stay male and things may be fine. No guarantees though.

if they are different species, you will need to re-home one.
Thanks for the reply. Oh so once they become female they can't become male?
But if they are male one can become female? Have I understood correctly?

I wouldn't know if they are the same species. If I add more pics would you be able to tell?

Thank you


Staff member
all clowns are born male. In a group the dominant becomes female. once female they can’t go back to male. That female will not tolerate any other females.
I assume these clowns were not in the same tank at the store.

the orange one is an oscelaris. The black I’m not so sure. its stripes are atypical (designer fish) and the black body covers the main distinguishing feature between oscelaris and percula, the wider black margins on the white stripes. The aggression may also be related to the different body colors.

How big are they? and were they in a tank full of tiny clowns at the store?

when I’m looking for clowns I’m looking for a tank of a lot of very small fish of similar size. I’d choose two that are small to mid sized for the group (1“ to 1.25“) definitely not the bigger ones and I want them to be close to the same size. This increases the odds they are both male. I always want to start with male although there is no good way to know other than if they are the smaller ones in a group. this increases the odds they will do well together.
Thank you for the detailed response, really appreciate it. The two clowns were in a small tank together. There where no other clowns but they had a royal gramma and I think a tang.

I made a mistake, I went for the larger ones. They are about 3 inches and I thought it'll be nice to have different colours.

Sometimes they are swimming around together, then out of nowhere they will get aggressive for a bit. And they are also shaking when they get next to each other but that was more yesterday.

Thank you