Lost one of a Clownfish Pair

[dmward1457]

I have had a pair of clownfish in a 16 gal tank for about 6 years. One of the pair disappeared(?) yesterday, no trace of it anywhere, whatsoever. Should I replace it immediately, and if so, should it be a younger, smaller fish or a larger, more mature fish? Thanks!

[Tired]

You should give it at least a week to make sure it's not going to reappear (check inside any filters, sumps, etc), and to make sure whatever killed it doesn't finish off the other one. 

 

You should not add a larger clownfish to a tank that's already had one clownfish for awhile. Clownfish are sequential hermaphrodites. In this case, that means they're all born male. Then, if no female is present, the largest and most dominant of the group will become a female. When adding a new clownfish, always pick one that's notably smaller than the existing one. That way, whether or not your existing one is a female, the new one will be a male. If you add another female to a tank with a female clownfish, they'll fight.

 

A similar concept applies to purchasing a clownfish pair for the first time. Always pick one that's much smaller than the other. That way, you don't run the risk of getting two females, and there should be much less fighting to determine which one will become a female. If there's no clear winner, they'll fight a lot more. 

[dmward1457]

Thanks for the help. That all makes perfect sense.