I thought spirostomum were only seen with the use of a microscope '? hmmmmmmmmmm.... I always find those small dark brown or red worms known as BLOOD worms in the filter material of the bio filter. They are the worm state of a type of midge that lays eggs in the water. They only seem to grow in numbers in the bio filters -- away from the hungry mouths of koi and goldies

I freaked the first time I saw them ! haha I thought they surely were some kind of blood sucking parasite worm.
--my ponds--