As for flipping within an aquarium club, that is another issue.
While I have offered fish and tanks to fellow club members (specifically for flipping) I can see the point of view on the pay it forward idea, but there is another perspective as well. If you breed fish for a hobby, you know that making new baby fish is the easy part. Finding a buyer and navigating pickup, shipping, loss claims, etc. is the real challenge. If someone in the club has an expanded market to sell fish to and is willing to work aquabid, pack, ship, and deal with retail customers, I would happily sell them my fish wholesale (with no hassle) so they can flip them for a profit (full hassle). I see that as paying it forward too. Many of us have the dream of turning a profit with our hobby, and if flipping some of my cichlid fry helps them make it, then I feel like I was part of their success too.