I have had mint cuttings growing out of the back of my 55g aquarium that is heavily stocked with Peacocks and Haps for the last couple of years. It has helped to keep the nitrates at a low level. I am careful to keep the mint leaves away from the water. I was recently told that even the roots of mint can release mint oils in the water and irritate fish. Any thoughts would be appreciated. Interestingly, while the mint keeps the nitrates low, the aquarium still has heavy algae issues. Thanks!