I had 11 cichlids in a 55 gallon (8 yellow labs and 3 cobalt blues zebras). One of the labs became alpha and kept harassing a couple of the labs so I thought I'd over stock so I got 3 kenyis and 2 victorian obliquidans and 2 jewels. It didn't help and I realised I had too much fish so I bought a 120 gallon. I read to add more hididng places so I loaded it with big rocks. Still my alpha targeted one lab and actually killed it. Then he started bullying another yellow lab so I took the alpha out. Within an hour the bullied fish became really mean and pushed all the other fish to one half of the tank. I was upset and put the alpha back to restore some peace even though that means having the bullied one cowered in the corner all the time. Now I'm having a problem with one of my blue cobalts...he beat up one of the other cobalts. What am I doing wrong...I feel that if I get rid of the aggressive ones, new aggressive ones and in my case even worst aggressive ones might take over and I might not have any fish left at all. Is 18 cichlids enough for a 120 gallon? Any one else have this problem? I thought yellow labs were peaceful...even my kenyi don't act this way.