I have eight radom cichlids in a 30 gallon...can i.?

It depends on what kind of cichlid it is. Some will bully tiger barbs, some will be okay, and some will even be picked by the tiger barbs. There is no kind of cichlid that you can have 8 of in a 30 gallon. The smallest commonly available cichlid is the shell dweller which you can only keep about 3 of in a 30 gallon. Tiger barbs need at least 20 gallons for a school of 6.