What are these white looking worm creatures?

Hey all! I created a brand new Vivarium about 2 months ago for my Spotted Marsh Frogs and have a small pond like dish inside it. I generally change the water every 2-3 days and was due today and I noticed these little worm like things moving about in the water. The frogs overnight must have been having a hell of a time as there was plenty of the substrate pushed into the as you can see, that’s the worst it’s ever been. I have Isopods and Springtails in but these things were moving like worms. Any ideas people? I have cleaned them out now but are good/bad for my frogs?

Hey all! I created a brand new Vivarium about 2 months ago for my Spotted Marsh Frogs and have a small pond like dish inside it. I generally change the water every 2-3 days and was due today and I noticed these little worm like things moving about in the water. The frogs overnight must have been having a hell of a time as there was plenty of the substrate pushed into the as you can see, that’s the worst it’s ever been. I have Isopods and Springtails in but these things were moving like worms. Any ideas people? I have cleaned them out now but are good/bad for my frogs?