Dymax Mini Vac siphon is an aquarium siphon that makes mini aquarium maintenance hassle free. Just a few rapid shakes on the tube and water from the aquarium will start priming out. The delicate nozzle will gently suck fish waste and other debris from the aquarium gravel bed without having the gravel or fishes being siphoned out. Frequent and small water changes are better for the fishes than infrequent or large amount of water charge as abrupt changes in water chemistry or temperature can be deadly to livestock. Adjustable flow rate.