Well, ty for the reply but I think you slightly misunderstood my question. Maybe it wasn't precise enough. Nevermind though because I've just come across heybude's article on this site "ISF Theorem" where he says 1. Our range is entirely dependent on what our opponent thinks our range is. Therefore a fish is not putting us on much of a range and all we can really do is think on the 1st level. We have a hand that is beating his range then we bet/call. If we don't, then we fold (call if we are drawing or since we are ahead of some and pot odds dictate). which if I understand it correctly confirms that vs fish we play our hand not our range.