I am not new to fish keeping but I am new to cichlids. I have researched several kinds and I was going to choose the B. Ram. Well while at the store to purchase them I noticed the convicts in a bottom tank. They had a pink convict and a ton of black. I decided I liked them better. I bought two. The pink and a black. I asked for a pair but I am not quite sure how to sex them. He told me the pink is a male. I looked at the two for two hours and still could not tell the difference. So I have two questions. First how do you sex them and second I wanted two pair in my 30 gal. Will they be alright in there. Thanks for any advice. Amy