I have, had, to green chromis but lately haven't seen the other one. Now IDK how often these guys mate but my clowns all of the sudden stay on the right side of my tank and don't even go into the middle. Like they are scared or something to go over there. When I started noticing that my 2nd chromis was gone I looked everywhere and could find him! Just the other day when I was feeding cyclopees he came out and was really skinny and ate for about 2 minutes and then went back into the rocks. The other one will swim around for a little bit but then always go back into the rocks! I am just wondering if it is possible that they mated and that the one is sitting behind the rocks and protecting her eggs where I can't see...? There are only so many places a fish can go in a biocube and trust me they have to be in the front because they are def not in the back chambers? Any ideas?