I have tried it in a 46G display tank and followed the instructions exactly and it just gave the fish some temporary relief but the fish still ended up being removed and placed in Hyposalinity. I now use it when a new fish shows signs of ich during the first few days of Hypo. At the start of hypo ich attacks like crazy and I have found that Stop Parasite does seem to distract some of the parasites long enough to get the salinity down to 1.008. Before doing this, I lost many fish during the start of hypo. I will not use it in any display tanks again, only in my hypo tanks.