New to cichlids. Set up a 55 gal. in my office about 8 weeks ago. Let water run filtered for about 1 week then added two packets of Biospira waited 2 days and added the following fish all about 1.5 inches.1 Yellow Lab 1 Blue Johanni 1 Yellow Acei 1 Albino Peacock 1 Fryeri 1 OB Peacock and a catfish. Everything went well for the first 3 weeks then the Albino peacock seemed to stop eating started hanging out up by the intake and I found him dead after the weekend. Added a Brichardi to the mix same size. The next week the OB peacock did the same thing. Found him dead on Monday and he looked like he had been attacked. I decided perhaps the Johanni or Fryeri were stressing everybody out though the Fryeri looked like he had been nipped at too. Removed them both on Weds this week. Now today I noticed my Yellow lab hiding behind my main rock formation all day and now he is hovering up by the intake just like the others. This is every Friday like clockwork - I leave knowing I will be coming in to a dead fish on Monday. I am at a loss. I check water parameters every 5 days and other than nitrates @40 right before the weekly 20% water change which I treat with Prime and let sit for at least an hour before putting into the tank. I skipped the water change last week but still lost the OB Peacock so I am unsure what the cause may be. Any suggestions or ideas?