They are just an aquatic worm that lives in the substrate. They don't normally affect fish or snails but are an indication there is something not right about the tank. When worms and snails try to get out of the tank there is usually a water quality problem. If the tank had a lot of rotting organic matter (fish poop) then that could cause the worms to try and get out and would also encourage protozoan and bacterial infections in the fish, and possibly cause high nitrate levels.
The easiest way to control aquatic worms is through regular water changes, gravel cleaning and minimising the food going into the tank, especially meat based foods like fish, prawns, bloodworms and brineshrimp.
If the tank is nice and clean and the worms are still everywhere, you can use my trusty and faithful friend that nobody here likes, copper sulphate. You remove the shrimp, snails and fish and then double dose with copper, wait 48 hours then drain and refill the tank a couple of times. Add some carbon to the filter after that and your good to go
And yes I know everyone is going to say no copper, but it works.
If you don't mind removing the gravel you can boil it to kill the worms and flush the tank while the gravel is boiling. then you don't have to use copper but there might be a few worms on the plants.
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Use the calculator in the How To Tips at the top of the page to convert drops to ppm. 1 drop = 17.9ppm if I recall correctly.
The easiest way to control aquatic worms is through regular water changes, gravel cleaning and minimising the food going into the tank, especially meat based foods like fish, prawns, bloodworms and brineshrimp.
If the tank is nice and clean and the worms are still everywhere, you can use my trusty and faithful friend that nobody here likes, copper sulphate. You remove the shrimp, snails and fish and then double dose with copper, wait 48 hours then drain and refill the tank a couple of times. Add some carbon to the filter after that and your good to go
And yes I know everyone is going to say no copper, but it works.
If you don't mind removing the gravel you can boil it to kill the worms and flush the tank while the gravel is boiling. then you don't have to use copper but there might be a few worms on the plants.
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Use the calculator in the How To Tips at the top of the page to convert drops to ppm. 1 drop = 17.9ppm if I recall correctly.