I caught and released a 6lb brown from a lake last summer that was bleeding from the gills. At the time I was unsure what to do as I have heard that trout are like paua in that they don’t stop bleeding. This fish swam 5m out into the lake before going belly up and sinking to the bottom. The lake at this point was several meters deep which ruled out the possiblity of me diving down to retrieve it, but I need not have worried because 10mins later it righted itself and swam strongly out into the lake..much to my relief!!..trout do stop bleeding and in my experience if you hold them long enough in the drink they will come right.