Hi, Not sure whether the styrene will have poisened the fish as i dont know if its toxic. But been as you have done large water changes and disconnected the veg filter i would have thought this would have diluted the styrene enough. Try seperating one or 2 fish if possible in a holding tank with purified water and see if they pick up, if they do, a full water change in the pond is in order. If not, it may be A. lack of oxygen or B. damage to the fishes gills from the sytrene meaning they cant get enough oxygen. So try adding extra air if you already have it, and if not, invest in a good air pump. best of luck
Posted on May 18, 2006, 5:04 PM from IP address 82.38.197.142