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these little squiggly worms appeared a week ago...
when i noticed the worms, i did a full tank cleaning, filter washed out with tap water, 100% water change, the worms went away... for like 2 days. now there's about 6-7 worms?
i have 2 RES, which get about 2-4 pellets daily and some green leaf lettuce.
the pellets get eaten immediately, but the lettuce are kinda messy as some bits and pieces get stuck behind their basking log and filter etc.
i think that's why these worms appeared, left over rotten food?

btw, i'm feeding them outside their tank, in a plastic container, they eat just fine.

my images are always oversized...

Looks kinda more like fly larva. There is a neat feature built into IMGUR, just add an l, m, s (large, medium, small) before the period in the file name to show a different sized image.

For instance I added "l" to your image

well, good news. all the worms disappeared after i did another water change. i added tap water, the chlorine killed all the worms, and most of them were dead below the tank and got sucked in the filter.

oh that is a neat feature of imgur, thanks Steve

If you have not determined the source, they will likely come back. Glad you found a way to deal with them!