I have some in a 25 gallon Aquarium with 3 small comet goldfish, I have a large amount at the top of the tank on a wire shelf with its roots in the water and its top out. I also have 3 medium sized one completely submerged so the fish can get at the leaves, I am hoping that by the time the submerged ones die I will have grown an equal or close to equal amount to replace it with. The goldfish seem to like hiding and swimming around in the tangle of roots.