I personally would never do this,however a question makes me wonder:could water snakes be kept with fish?I have read water snakes are sensitive to blisters,though.What about elephant trunk snakes?fully aquatic,and could possibly be kept with medium to large fish.Possibly young anacondas.YOUNG!!!As seeing they spend most or alot of their time in water.Oh yes,please dont tell me it won't work,because I would vever do this.Unless it was possible 