i've had a ton of aquariums in my time so i can telly ou that these are in fact planaria. they are a result of overfeeding and/or decaying plant matter in the water. they are almost always present, but not in high enough numbers to show like that.
usually you can cut down on their numbers by feeding less and removing dead plants as well as changing the water. they *seem* to be harmless, but from what i have heard they will attack fry/tadpoles and shrimp. never had it happen to me though.
usually you can cut down on their numbers by feeding less and removing dead plants as well as changing the water. they *seem* to be harmless, but from what i have heard they will attack fry/tadpoles and shrimp. never had it happen to me though.
