Tiny worm parasite in my tank

Question
I have noticed this substance on the walls of my fish tank. At first it looks like tiny things waving in the current stuck on the walls, later to find all these very tiny worms crawling on the walls. I have been told they are "flatworms" and are harmless to my fish. But I want to get rid of them. They are unsightly. I have already siphoned the gravel, cleaned the filters, and done water changes, only to have them always reappear. I can't use any type of parasite killer in the water because it would harm my blue crayfish. I heard that I should get a gouarmi that it would eat them off the walls. Is this true? Would my crayfish try to kill the gouarmi? Is there a treatment that would kill the worms, but not the crayfish? I'd rather not have to buy a gouarmi. Any suggestions would be appreciated.

Answer
Hi Jeff;

They are indeed a harmless flatworm or nematode. There is no chemical or medicinal method to get rid of them. They are so hardy they will survive bleach treatments. I've seen that personally. I was shocked. The only effective way to eliminate them is with aggressive vacuuming and water changes. The food source (waste and extra food) must be removed and less food should be added to the tank. You can do all cleaning you want but if you don't cut back on food they will return. At first you will see more of them but it is because they are getting desperate to find food and exposing themselves to hunt for it. They will eventually starve and die out.

I have heard these crayfish can be pretty aggressive predators so it's up to you if you want to try adding a gourami to the tank. In my opinion it's like putting a bandaid on a gaping wound though. The symptom is hidden but the serious underlying problem remains. Hiding the excess waste trouble by eliminating the worms is really not the best way to go. They will starve out with diligent cleaning. If they come back, do more cleaning and cut back on food even more.

Good luck.....

At Your Service;
Chris Robbins