Yup, definitely either fleas or lice. Mites on rats are invisible to the human eye. I’ve (unfortunately) had both fleas/lice and mites infections, and with the mites, you could not see them at all, but the rats were super itchy, losing fur, and had some scabs. The bugs you could see where way more unsettling as they crawling all over my poor boys’ backs!

The best treatment course is Revolution from a vet. It might be a bit more expensive but home remedies often aren’t as effective. Every time I’ve had a rat treated with Revolution, the bugs are dead within 12 hrs (have stopped moving on the rats) and have fallen completely off their fur completely within a day or so.

You should also do a deep clean of the cage so they’re gone for good. I’ve heard that lice/fleas require slightly less rigorous cleaning than mites, but I’ve never taken any chance. If you use pine/paper bedding, you should probably buy a new package as it’s possible the mites originated from this. I clean the cage with a white vinegar/water solution, I’ve heard some people use watered down bleach but IMO that’s slightly harsh (especially on rattie’s sensitive lungs) and I’ve never had a problem with the vinegar/water. Clean all plastic toys like huts or hides thoroughly, also with the solution you choose to use, and if you have any wooden toys in their cage or play area freeze those for 48 hrs. (I’ve always just thrown them out so as to not take any chances.) You’ll you’ll want to replace their bedding more often in the first few days just to be absolutely sure that no fleas/lice remain.

Good luck! :) I hope your ratties find some relief. I’ve heard that putting vegetable/coconut oil on rats can help smother the mites, but I’ve also read that doing this can cause rats to have issues regulating their body temperature due to the oil.