Do you mean grow in a fishtank as in use a fishtank like a pot? Or do you mean use it for hydroponics? Either way, I would advise against it, as you are going to have to block light from getting to the roots, and either way you are talking about would probably allow a good amount of lights to get to the roots. I dont know, maybe someone has done this and can contribute to the project, but I just think there would be too much light getting to the roots. If I were you, I would grow in like an old dresser or wardrobe (thats what I did my first grow, which just finished) and set up a neat fish tank to look at after you smoke your homegrown :jointsmile: