I found my tank also got small little white worms, about the diameter of a hair and up to 1/2" long. They would attempt to swim like little white snakes. Once the fish noticed them, they eat them right up. Now, the fish almost fight over them. I've seen fish sprint 6" inches to eat one of these guys.
This could describe any number of worms. It's kind of like saying you found a little shrimp or a little fish. If you can't take a picture of them, then it would be helpful if you could give a detailed description of them. What color are they? How big are they? Where are they in the tank? How do they appear to move? Do they "inch" around like an inchworm or wiggle or what? Get a magnifying glass to look at them up close to get a better view of their body shape. Are they flat or round? What's their tail look like? Their head?
The better you can describe them, the better chance you have of getting help. Otherwise, the best anyone can do is throw out the names of a bunch of different worms, and you'll have to look them all up to figure out if any might match what you have if you.
VickiRena Filstar pimp #142 (four XP4s/three XP2s/one XP1) Eheim pimp #301 (Pro II 2128) Victor pimp #27 (VTS-253B-320)
it sounds like the tiny nematodes i got with floating plants or dry'd flake food that sometimes survive as cysts in. the heplessly wiggle i nthe water column searching for a dark place. and a realllllyyy small baby tetra in there that isn't big enough to eat shrimp and watch it FEAST on the little things. they are otherwise harmless