Two of the 3 fish, JD and RT, are skittish fish by nature, and their shyness is reinforced if you only have 3 small fish in a big tank. Shyness can be contagious. If one fish is skittish, it can scare other fish to respond the same. One solution is to add more fish, specially the greedy juvies who are more interested in food than to hide. The best dithers IME are more cichlids to compete for food and territories. Another solution is training. Just before you feed your fish, wave your hand or move back and forth in front of the tank for a while to condition the fish into association with movement to food.