3 of my discusfish are in puberty. The other two are a little smaller and they don't really bother all that fuzz. I have this tank for about 2 months now, but the three oldest Discus fish have been together in this tank for since they were tiny (I bought the tank with those fish in it). The other two were added for 4 weeks now. I'm wondering what is cousing this aggressive behaviour between them. Could it be that a pair is being formed, and if so, which one belonges to witch one? Is there anyone who can see if these fish are male or female? I'm really curious about that. I'm feeling a bit sorry for my blue friend, for it seems that everyone hates him, although he is challenging the others himself. Besides all my questions, off course I would like to know how you like my dear fish.