Ok, please do not try this without checking it out first. Here is my story. I had this problem more then once. The first time I got these crawly threadlike things in my soil (ie. Last summer), I ended up throwing out my Thanksgiving Cactus. So last November, I purchased a few more Thanksgiving Cactus from the supermarket. I noticed those pesky tiny fruit flies/knats flying around my plants. ( they usually lay their eggs in the soil ) Well that was it! I mixed a combo of rubbing alcohol and water and sprayed the surface of the dirt on my newly purchased plants really well. I have knat/fruit fly traps all over...ie.. Near each plant. For the first time since the Fall, I recently saw the first little bugger and put out my traps. I may do my alcohol/ water spray again. But this is risky. It did not kill my plants, but it can kill them if you overdo this. Proceed at your own risk. Best to try to control this problem. I do not think you can completely avoid it if you have live plants in the home. They LOVE organic soil and there may be unhatched eggs in the organic soil you buy at the garden center to transplant your thanksgiving cactus into a new pot in the Spring. So far I have NOT transplanted anything. Nor have I fertilized anything. These tiny fruit flies/knats come in through screens or with your groceries/fruit that you buy at your local supermarket. They can even come up out of the drain in your sink! I have added photos of these traps. They work well so far for me. You can purchase them at Home Depot or True Value Hardware.

Symphylans fit that description except for the length-- they're longer than one mm. Pupulations are enhanced by lots of manure. You might look up info on them to see if they fit.

Use some seaweed mix with fish emulsion and in a few weeks you will be fine best to stay away from Miracle Grow if you plan on actually eating from your plants, peppers do so much better on natural components rather than synthetic ferts... Here is a link that might be useful: Organzmo Peppers

I have a similar problem - I’ve attached four photos: two make the insect look oval and brown, but the other two make them look more silver. I am not sure if this is just due to the color of the background. With the naked eye the insects in all four photos seemed to be the same insect. I am reaching out because the plant these insects are inhabiting (an anthirium) is slowly dying. It has dropped 80% if it’s leaves and has stopped putting out new growth. I am concerned that the insects are feeding on the roots, as I don’t see any insect damage to the leaves or “branches” of the plant. I inherited the plant from my grandmother when she passed about a year ago and it appears to be very old and has 8 inch long “trunks” and was very full when I originally took it home. A few moths ago, at the recommendation of a local nursery, I replaced the first 1” of soil with sand and refrained from watering my plans for roughly 2 weeks. I have since gotten back to a once-weekly watering schedule allowing the surface to dry between waterings. Although I no longer see these insects on the surface the plant continues to struggle. Recently, when I lifted the planter, I found them scurrying around on the underside of the pot. Any help identifying or understanding how to get rid of them would be very very much appreciated!