worms

Hello all,Today I discovered a type of worm on my filter pad. I am
using the Emperor filter system on a 29 gallon tank with lots of
plants and mixed community fish. No new plants or fish in over a year.
The only difference is that I am occasionally feeding frozen
mosquito larva. These worm are on the foam biological filter pad
behind the floss/charcoal pad and appeared to be feeding on the
material on the pad. There were only about five or so. They were
about the diameter of sewing thread , an inch or so in length and
bright red. I am not worried, just curious. Thanks. Richard