Fluval Hang-On Breeding Box is a breeding and spawning box that is hung on the outside of the aquarium glass. Especially for small aquariums this is a great advantage because there is little space in the tank. Water circulation can be ensured with an aerator pump (not included). If the attachment tank is used as a spawning tank, a V-shaped protective grid can be used to protect the spawn or fry. A lid protects the fish from jumping out.Fluval Hang-On Breeding Box 1.9 L+ small tank to hang on the aquarium pane+ for rearing, isolation, acclimatization+ usable as spawning tank+ removable V-shaped grid+ for frameless aquariums from 5 to 10 mm glass thickness+ for aquariums with frame up to 47 mm+ dimensions: 260 x 90 x 125 mm (length x depth x height)+ volume approx. 1.9 L+ perfectly closing cover plate+ Water circulation by means of aerator pump (not included)