JA-RU Magic Grow Fish Aquarium Kit (2 Pack 2 Random Colors) JA-RU Magic Grow Fish Aquarium Kit ( 2 Random Colors) Fish tank is plastic the cover is not removable and it measures 3 1/4 x 2 x 1 1/2 . This is a fun activity for children 4+ years with parent supervision. See last 2 photos of fully grown fish. Manufacturer recommends not to use hot or warm water. Remove stopper on top of aquarium and fill with cool water. After a few hours the fish will begin growing! Allow a few days for maximum size. To keep water clear change water every few days. When water is drained off fish will gradually shring back to original size. Toy can be used over and over.