YSK flushing fish is a really bad idea

If its alive youre basically abusing the fish because it can very much feel pain especially the chlorine in toilet water.Also the fear of becoming an invasive species

If its deaf then you run the risk of poisoning your waterways(nobody wants to drink water in which a fish rotted in)

http://ift.tt/2lff0Oy http://ift.tt/2y3DYqa http://ift.tt/2lhnGDW

If the fish is dead your best bet is to bury it.if not then you can euthanise it using a clove oil or alcohol bath(both should be properly researched)

Sorry for poor formatting.Am on mobile