hi all, i have a question for you. i have a fishtank in which i have 2 cichlids in, i believe they are africans. ive had them for about 7 months now. the thing is i bought them together when they were about 1 inch long and they have been fine till now. 1 of the fish is digging up a hole for itself and it wont let the other fish swim around, it confines it to one corner of the tank....why is this???