Right, I think I met Bladedge, when Judai was walking him...

[Atem takes one piece of tuna for himself, careful to eat it over the side, not over the water. It'd be very unappetizing to drop it, and a waste of really good tuna.]

Have you thought about putting them up for adoption...? If they're too much for one manticore to manage, there might be other monsters who'd be willing to look after them.