Nice looking pups. The last pic, they look skinny/boney for sure. Bloodworms are bette than nothing mate, but not very nutritious. Grab some garden worms asap from a fishing shop or even dig your own and wash well before chopping up to feed. They should go mad for the large worms and they are great for bulking up young rays. I'd suggest adding in a few small sinking carnivore pellets with each worm feeding, even if they don't take them straight away, it'll help to encourage pellet feeding. Nice one