Electric yellow in the house

Or in the tank I should say. I picked up an electric yellow cichlid on Sunday to take the place of my fallen convict cichlid. I thought the fact that the yellow fish is larger would curb the orange cichlid's aggression. Alas I think I was mistaken.

As you can see in the third photo the poor thing has already set up residence in the previous tank inhabitant's favorite hiding place - up by the heater. I hope the aggression abates - I will be really sad to find another violated fish in my tank!

I was quite disturbed to learn that convict and red zebra cichlids (the orange fish) are extremely incompatible. I sure wish that Petco guy had told me that in the first place. I guess I'll be more faithful to my local dedicated fish store to avoid such uneducated sales.