Bloodworm in gills every time he feeds.. Also very skinny

Every time I feed my axolotls (I have 2) the one axolotl Royston gets bloodworm trapped in his gills. This happens nearly every time but only to the one axolotl.. I manage to get it out or he dislodges it himself but a few weeks ago a lot of his gills on one side had gone missing I'm guessing the other axolotl had seen the bloodworm in the others gills and tried to get it.. Also the same axolotl Royston has been tiny since I bought him (about 5 weeks ago) he is definitely underweight and no matter how much I feed him he doesn't put weight on.. It's getting to a point now he is a completely different size to the other very healthy axolotl.. Please help

Can you take some pictures of Royston, so we can see if he is too thin or not?

If they are over 4" you could try feeding them with small earthworms - a little cleaner to feed and won't get tangles up in gills.

They are over 4" as you can see there is a massive difference in size this is Royston the next pic will be the other.. When I got them both Royston was already smaller than the other they were kept on gravel in the store and he seemed very ill from the start I think he may be blind in one eye.. I've done my best to get him back to help but he just doesn't put weight on I've noticed him vomit his food up when I fed them both earthworms I gave him2 small ones and he still threw them up.. I'm not sure if he has been doing that every time he eats so now I've segregated him so I can tell exactly what goes I and out of him he doesn't poo much at also I don't know where the food is going?

The other axolotl I got the same time

OK, he is way too skinny and you need to fatten him up. And at his size blood wroms are just not enough.
Try:
1. Worms. Some worms (dendrobaena or red wrigglers) can taste bitter to axies. Make sure you wash them thoroughly. If he still won't take them or regurgitates them try dipping the worms in boiling water to kill them first - it will stop the secretion of the bitter slime and make them more palatable. You don't want to cook the worm, so a quick dunk or 'blanching' will do fine.
2. try feeding different things - wax worms or maggots, river shrimp (also called ghost or glass shrimp), feeder fish (after quarantine).
3. try pellets - trout or salmon pellets if you can't axie-specific ones. Beware though, uneaten pellets left in the tank will send your NH4/NO2/NO3 levels through the roof.

Feed him every day until his body is as wide as his head.

Hi, I just thought i'd let you know that i had a poorly axie who was extremely skinny when i got her from the aquarium, hence why i bought her....I fattened her up on raw fresh salmon (stressing fresh not smoked) She showed no interest in any pellets, earthworms, bloodworms etc so i tried that and she loved it! I cut it into thin strips and fed her as much as she liked everyday and it didnt take too long for her to gain heaps of weight and finish growing. i just got one piece and cut it up and separated into little bags to freeze so i could just use a little bit at a time...$6 worth lasted a couple months. now she eats heaps of different thing and is super healthy (I'm guessing...lays eggs every 3 weeks lol) ...worth a try

I've tried him on earthworms small ones and larger ones.. The female axolotl eats them fine and loves the but Royston just seems to sick them back up after about 20 minutes.. I fridged him for over a week and he never passed anything at all I don't understand how he can eat but not poo and still lose weight

If he eats, but doesn't poop, and keeps losing weight...

Now, just an idea, don't take my word on this, but it sounds a bit like a parasite. Anyone else thinking this?