how old is the fish? what are its tankmates and what size is the aquarium? festae arent the most agressive fish at a young age. stress can cause them to hide and be timid at times. what size are the other fish thery are housed with? is the festae the newest addition to the aquarium? you cant just teach a fish agression either. using feeders, other live food, will hone a fishes hunting or striking skills but will also hone every other fishes in the tank. without knowing your set up id say add more line of sight breakers in the tank. rocks, driftwood, slate...