My mom has a koi pond in her backyard. Her boyfriend changed the water earlier today... and i think he left some soap behind. The pond is sudsy and one fish is dead, one is dying, and one seems to be doing pretty well. Is there anything i can do for the dying one? I put it in a bucket of fresh water, but is there something available at wal-mart (the only place open right now with fish supplies) that i can put in the water to try to save him? Please respond quickly... i don't know how long he's going to make it. It's so sad to see him like this.