I've never had any problems with coppersafe and the lfs I used to work at treated all its tanks with copper for various things, 1 it keeps inverts away, permanently, its fine for bichirs, arowanas, and loaches I know for sure, dats should be just fine also but I can't personally vouch for that. Coppersafe if its mardel or some high end brand is one of the best treatments IMO ~Trent