I wouldn't consider putting it into a tank that size until it's at least a year old, and closer to 3 feet. Of course there are some bps that don't take well to tanks after tubs. I had a new girl in a quarantine tank, who was used to racks and tubs. She did NOT eat well in the tank. Once she cleared quarantine and went into the rack she developed a SUPER feeding response!! Congrats on the free tank!