For most species, it work in the long run. Clowns are very territorial--2 pairs in such a small tank will be a battle. If you want a pair, you will have to get them together, or you'll face the same problem. You could try having 4 ocellaris clowns--with them, the dominant fish will become female, and the remaining fish will stay male, in her harem. I wouldn't try it, though--that tank is likely going to be a battle ground.