It is often very difficult to catch an individual fish--especially in aquariums with a lot of rocky decoration such as reef tanks or aquariums for African cichlids--without completely destroying the decorative aquascape. You can bait the Aqua Medic Fish Trap with some food, and as soon as the desired fish has entered the trap the closing mechanism is simply released by hand. The trap is constructed in such a way that it can be removed from the aquarium with the fish inside. This method considerably reduces the stress on the fish. 5.9" x 2.7" x 2.7".