Do they look like this?? If so, these ARE fungus gnat larvae. Generally, they are found in potting soil that is kept overly moist, which is not something a Haworthia or other succulent would favor. What kind of potting soil are you using and how often do you water?

Fungus gnats and their larvae are very easy to control - simply use a very fast draining potting soil - for succs, I'd suggest something like the gritty mix (no peat or coir or compost!!) - and water only when needed. And no pebbles or rocks at the base of the container! Contrary to common thought, these actually impede good drainage (by raising the perched water table) rather than improving it.

And while the larvae does feed on plant roots and other organic matter in the potting soil, they seldom do significant damage. The damage often attributed to these creatures is more often the result of excessive soil moisture, causing root rots and other fungal problems. Change the soil and water less often and you'll be fine.

@gardengal48 no they do not look like that. they dont have little 'arm things' on them like the picture. They kind of look like normal outdoor worms, but like 4 millimeters long by 1 millimeter wide. they just squirmed around. i looked up the gnats and the larvae and they said the eggs get laid on the surface and there would be flies, (gnats) but i dont see any flies, eggs on surface, worms on surface, or anything like that. the only time i saw them (just this morning) was whenni watered the plant and water came out of the bottom and there were millions of them in just a little pool in the water dish in the bottom. but yes, anyway, they dont look like the picture they are just thin worms with no arms, visible mouths, or anything. the only way i can describe them, though, is almost clear whitish color. no solid white, its almost seethrough. i will update this comment with a picture if i find one. Also, where you said dont put rocks at the bottom, i have rocks down there ._. and also on my Mammilaria cactus, too, but its doing okay, nothing wrong with it. Also, could the 'overwatering' be because the pot is too big for the plant, thus too much water? i will also post a picture of the soil i used.

@gardengal48 heres the soil. it is kind of thick-ish. also i water it untill water comes out of the bottom of the pot and i water it maybe once every week or so or if completely dry. i have a little stick thing i poke into where the soil meets the pot to see if the soil is dry all of the way through. And if these are what you say, and theyre dangerous to my plant, should i repot immediately?

@gardengal48 found an almost exact picture:

almost exactly how small they are.

(also so sorry about multiple posts, i cant put a picture on a post im editing on..)

Perhaps pot worms.

@Jean at first i was thinking pot worms, but in any picture or video i see, they are waaaay longer than the worms i see here. I am going to wait this one out for a while and see if they get bigger, or i start seeing gnats, etc. also, if these are pot worms, are potworms harmful to plants? i hear they are harmless and are just 'things that live in damp areas' but i just dont want my plant to get rootrot or get the roots eaten, thus slowing growth or possibly stopping growth temporarily.

@Jean yeah the only problem is.... these arent even long. they look exactly like the tips of toothpicks, but they are only about half a centimeter long. not long AT ALL. every picture i see have longer worms that look about a centimeter and a half to an inch. these are half a cm. does this explain a little bit more? idk how else to explain them :\, but they dont look like theyve done any damage so far, so im gonna stay with potworms, but if the plant starts wilting or yellowing i will change the soil and repot immediately. Thanks for your help :)

was i outdoors?? .. what about regular worms??? ...

i dont understand why you flood the pot so often ... that there is so much water running out the bottom ...

where are you.. and are you taking it indoors for winter????

ken

@ken_adrian Adrian MI cold Z5 , it is indoors. i dont flood the pot, theres a few drops that come out the bottom and in those drops, there were a bunch of worms. i dont know about regular worms, although i did see somebody say that young earthworms are transluscent white. i got this cactus about 4 to 5 weeks ago and everything was fine. just a few days ago, though, (the soil was completely dry), i watered it there was worms in the water that dripped out of the bottom.

That description doesn't match the picture of the penny.

Please post your own pictures so that we can see size and shape (include something for reference). If you aren't able to do that, likely you know someone who can help you. Perhaps a neighbor, friend, or neighbor.

@Jean yes i would have posted a picture already, unfortunately i have an older version of device so the resolution is absolute rubbish. it wouldnt evem focus on the worms, and the only way i could see them is to water the plant again (trying not to for a long while because cacti can survive with little water.) and the worms arent on the top of the soil whitch is extremely odd. but yes the ones on the penny are ALMOST exact.. just maybe cut them in half and theres what worm i have. if you cant solve this situation any more than you already have.. i understand. i already know what to do from what youve told me. repot if things get bad or start to wilt and if i start seeing flies and stuff. thank you for your help ^-^ i really appreciate it!

Those critters on the penny are the size of potworms.

If that's what you have, you won't have flies.

If you end up with flies (fungus gnats), your Haworthia's roots will rot and the plant will die.

@Jean so are fungus gnats smaller than potworms? because if they are gnats i dont have flies.. and if they are too small to be potworms then i dont know

Decrease your stress and do yourself a favor by taking some of the critters to your county's Extension Service office where people can look at them in person.

You can locate that office with this interactive map:

http://npic.orst.edu/pest/countyext.htm

@Jean I might just do that. thanks for all your help, Jean.

Could they be nematodes? I've seen some that were really small and different lengths.

@iandyas (Zone 9B - QC) thank you for your suggestion. thats another thing i was thinking they were, but i noticed the tips of the leaves starting to brown, so i repotted it. problem solved. :)