I frequently post on subjects I have no experience in to stir ideas, conversation or to reiterate old knowledge. I don't think you need to keep fish to appreciate and speak about them, how you present that does matter. I don't think we should have to have ryansmith reply to every cichlid thread, or RD to every nutrition thread if it's already been talked to death. Fishkeepers don't need to keep every fish to have some introspection on it, but the query can set a prerequisite.