I need some help with my new tank. We recently got a new tank and inside I have a clown knife, 2 convicts, silvertip shark, and a couple other small ones waiting to be eaten. I went to the LFS looking for a male n female convict. I'm not sure I have them though. I've done research but I'm not sure if I was right. Also they are very small so it is hard to tell. I noticed the smaller one was almost acting dead lol... it was standing on its head. At first they were kind of swiming in circles with each other and getting the feel of one another. now the larger one seems to not like the smaller one. The larger one does not have a pink belly and the fins are more pointy and bigger. the small one has yellow spots on it's belly and its fins are more rounded. How can I be sure I have a male and female?