Yes, I too agree it is morally wrong if they grow into 7inches & someone keep then in a 1ft tank but seems ok if I keep them from young before they grow bigger(as advise from the shop owner & another season reefer's advice).
I was planning to have a bigger tank by end of the year after I move house. All in all they didn't make pass 2days either.
Does sifu out there kept lionfish from young can advise what went wrong? One of ah beng's worker told me someone in SG succeeded in training his lionfish to eat pellet.