My newt isn't eating after metamorphosis - when should I worry?

So to preface this, I have a batch of 10 Cynops cyanurus babies. One of them has gone through metamorphosis, is eating well, and is generally doing great. The second one to go through metamorphosis never really came out of it - it wouldn't go back into the water (and freaked out every time it was in water) and wouldn't eat for over three weeks (though it had become extremely thin) - and ended up dying. I have three more currently going through metamorphosis and one of them is about two weeks into the process, very thin, and still very hydrophobic. Two days ago, I offered bloodworms and it went to bite at one but then lost interest entirely when it didn't make contact. It hasn't even looked at the food since then. Should I be worried and if so, what should I be doing to try to get it to eat?

(Currently, I have all of these newts in separate containers with a small piece of land area and about 2 inches of water. I do a 50% (at least) water change daily using spring water from the store. I fed them baby brine shrimp when they were small but now I use bloodworms.)

Have you tried feeding them live blackworms? They are sold at good tropical fish stores (not Big Box), as well as online. Newts love them, both in the water and on land. If you can get them, put some on a paper towel with the newt. If live blackworms are not an option; Walmart sells small baby crawlers. Try cutting just the tip of the worm off and put it on a toothpick.

C. cyanurus should do fine in a tank with a sponge filter, plants, and fed blackworms. A cor bark float can be added. Normally they stay totally aquatic and do well in deep water.

What kind of plants do you recommend? Also, I'll see if I can get any live blackworms - the little one is still refusing to go into the water so something on land sounds great!

Update: The little thing is still not eating. It's still climbing up on walls and trying to get out of the water. Two of my other baby newts have entered and finished metamorphosis in this time. I'm going to keep offering food but I don't know how it's lasted as long as it has and I have no idea what's wrong with it.

How do you have it set up now? I would set it up terrestrially in a tank seeded with dwarf isopods, springtails, and white worms. I'd try feeding tiny crickets and small chopped earthworms.

I have it in a small tub with a few plants and some land area. I did get it to eat one bloodworm yesterday (I dangled the bloodworm in front of it and the baby gulped it down after 10 minutes) so hopefully it's going to start taking food more regularly.