The general way of measuring pp dosage is grain of pp per ml water. I've never used it to treat fish. It's used to sterilize stuff.. like cooking equipment if you're out camping or something. So for instance, two grains for a pot. It's hard to measure PP exactly because of the size of grains they come in. Light purple should be roundabouts right for minute dip. It's not as painful as 10% Hydrogen peroxide, that's for sure.

I learnt that pp + glycerine = fire from a dude that used to work for my parents when I was a kid. He was showing me this magic trick, he started a fire by waving at a clump of newspapers.... i later found out he used pp and glycerine so the fire is delayed until he waves his hand..