I've made a huge mistake

So here's the deal. I have two juvenile axolotls living in a 10 gallon together. Up until last week they were very active and had ravenous appetites. About 4 days ago I tried feeding them their normal meal of earthworm bits. Neither ate, so I just figured they weren't hungry. 4 days later and they still haven't eaten.

I also have to point out that I recently had a huge population increase of Hydra and Planaria. I read up in multiple forums that the use of fembendazole (de wormer) is safe way of combating that problem, and it worked like a charm. Unfortunately I found out that I dosed 10x the suggested dose 2 days later. (confused 1 gram with .1 gram)

While its not a direct correlation, there's a pretty damn good chance that I have inadvertently poisoned my axolotls. I've already done two water changes on my tank, but they still wont eat.

Tomorrow I'm going to replace all the water and substrate and hope for the best. I'm at my wits end.

If anyone can suggest some solid advice it would be much appreciated. I don't want to lose my little friends. I just moved to Florida and they're really all I have.

There is no antidote to fembendazole, but overdose is not usually fatal in most animals according to the toxicity data I found.

It looks like the main problem could be anaemia, but this will resolve itself over time, as will their appetite. They can go without food for a couple of weeks without any real harm.

In the short term you're doing the right thing in changing the water - all of it and the substrate. Keep them in cool clean water.

But please don't be tempted to use chemicals again - all you need to do with unwanted little invaders is scopp them out with a fine net.

Also, these little unwanted critters usually appear from dirty tanks, check your water parameters regularly and do weekly water changes. 10 gallons is too small for 2 axies they are in need of at least a 20!

Okay thank you that's actually quite a relief. I'm keeping them fridged for a few days for now and I'm going to redo their tank today.

Also I may be getting rid of my Bichirs in my larger tank (or else moving them to a 40) so a 20 gallon will be freeing itself up soon.