Hi Kenya,
When you switch filters it is a good idea to cram some of the media from the old filter in the new one if possible. It takes awhile to cycle the new filter. Feeding them earthworms will fatten things up but can also cause a problem. If you bounce around on the food it is tough for the salamanders digestive system to gear up for the food. Switching foods is o.k. but do it in moderation.
I think you are on the right track. Fridging isn't a bad idea. Personally I never do it because my wife doesn't care for axies in the fridge. If you back off on the food a little it shouldn't take to long for a 20 gallon tank to handle the bioload of 2 small axolotls.
I tried, but the sponges wouldn't fit. That's why I let them float, I just wish I knew to do it longer. And I didn't even think of that, like how you shouldn't switch a dogs food too quickly. I am now feeding a little of both. Pellets are easiest when they are in tubs and not on sand.
They are in the fridge now. The leucistic is already getting it's color back. And I can see a little more gill filament. Will it grow back? My mom doesn't care for them either, mostly because they are in a plastic container that holds over 2 gallons, and, takes up a ton of space. But she must know that arguing with me about it will be a lost battle. The poor woman has two different brands of bloodworms, brine shrimp, and even an ice tray purely for dechlorinated water. Not to mention the axie pellets and earthworms in the fridge. The only huge disadvantage of fridging is that now it's going to be even harder to put weight on my little wild type. The leucistic still eats a little in the fridge but the wild type will do a few pellets at most. UGH.
Off topic, but, are my two from the same parents? With the size difference it seems that the wild type might be a little younger. It's not just skinnier, it's much smaller. Besides, I have no idea why, but I identify the leucistic as female [not just because of the pink gills!] and the wild type as male. And one day if they breed I will probably keep a few eggs and raise them. I know a few people who would love to have healthy axies, there are a lot of really awful mom and pop stores and no one smart trusts them, especially with amphibians. But if they are directly related, I don't know. It would be weird to think of them as both the father and uncle of the babies, you know? LOL.
Thanks to everyone for their advice and especially their support. Though I still feel very guilty, at least I'm not too panicked anymore.
Earlier I went to do a water test, and when I used the eye dropper to put water in the tubes, I saw coloration at the bottom. I feel like I rinse them well, but maybe not well enough. I think it might have been screwing with my results, so I put some plain dechlorinator without additives and such in a bowl and am letting them all sit. And I am about to do another test. Will post results in a minute.
Thanks again everyone!