Floating Axie :(

I know there are a lot of topics on this, but my problem seems slightly different.
I have four 2 inch axolotls.
When I first got them, I was feeding them dried bloodworms every morning when I woke up by reaching into the tank and feeding them one. The bloodworms don't absorb water or sink, and since the axies are so small, they end up floating to the top as well.
It seems like they got used to being fed and near the top when there was some light in the room, so every morning, they come to the top, and after I feed them, they sink down later.
But one of the axolotls isn't sinking back down. When I saw him floating for more than a day, I put him in a little tupperware container to look at him. It's very obvious that he has air trapped in his stomach. It seems like he is constipated, because the dark spots in his stomach haven't left. They aren't big enough to eat gravel, and they don't eat off the bottom, so I know that's not it.
Only this one axolotl, out of four, is having this problem, so I'm not really thinking it's anything wrong with the tank.
I had put him in the fridge for about a day, and he sank down to the bottom of the container, so I put him in a bag and let the water temperatures even out, then I put him back and he seemed fine. But overnight he got another air pocket. I tried to massage his side a little, and he burped some air out, and he sank down a little. But it seems like there is something wrong with him.
What should I do?

Don't hold me to this as I don't own an axolotl but I seem to recall reading online somewhere that it said once they eat again the air should go down again and sometimes they just get a little air trapped.

Although it would be better if someone with an axolotl could reply to you...I hope the little guy is ok

The first thing i would do is to change the diet. Freeze-dried bloodworms are not suitable as staple. The drying process robs it of a lot of essential nutrients. In addition, this may cause constipation and also gas buildup in the alimentary tract due to ingestion of air while feeding on the surface.

The best thing is to is to feed live blackworms and earthworms. They will meet all the nutritional requirements and would resolve the problem of gas buildup, constipation or excess surfacing.

I would advise against massaging the axie. They are very soft bodied and any excess pressure can cause more harm than good.

Have a read through this. http://www.caudata.org/cc/articles/why_larvae_die.shtml