Rescued Axolotls need help rehabilitating

Hello,
I inherited 3 axolotls from work that are a little run down. I think they had pretty bad water quality and unknown nutritional support. I've researched online and I have them in the fridge in individual containers of .5 gallons that I change completely 1-2x per day. The water is tap but it's treated with Safe. In addition to the Safe the water has salt added at a ratio of 1.5tsp per gallon. They are looking better every week but it's slow recovery. As far as food goes they aren't eating much. I've been trying 1/2 a nightcrawler but only one has eaten it. They've eaten a little frozen bloodworms but aside from that very little food, I hope this can be attributed to the temperature.

Is there anything else I can be doing, or should I stop doing what I am currently. Also, can I keep them in the fridge indefinitely?

These guys are cool but I plan to just rehab them enough that I can find them a proper home.

Any help is appreciated.

Whoops, is this the wrong forum? I see an Axolotl help forum.

I've read in a lot of other threads on here that friding slows down their metabolism a lot which is why they lose their appetite a bit, a slow metabolism means food requirements are lower than usual so it should be okay that they're eating *something* even if its not a lot?