oh the silly names the stores give to cichlids. they mean nothing and it's always best to use the latin name so others will know what species you're talking about. there's no such fish as a "soco" cichlid. what you've probably got is Pseudotropheus socolofi. the snow white aspect is probably supposed to mean that it's an albino color morph since generally, this fish is blue. the "yellow" cichlid is perhaps Labidochromis caeruleus 'lions cove'. these are African cichlids and should be maintained in groups of at least 4 ... one male and three females. thus, you should have a minimum of 8 cichlids representing these two groups. unfortunately, that's far too many fish for a twenty gallon tank. their hiding because they're not being kept in a 'group' as they should be.
