I had hydra in my one gallon tank with NO lights , other than a kitchen light on sometimes, and there was NO life in the tank , I had took out the betta 4 mtsh ealier and was just running the sponge filter with NO food . Thier is a treayment with a god dewormer for small puppies, its powder form, and you could find this info doing a search for hydra and how to kill it , you only can use a TINY pinch once and then water change, tehn see if you see' anymore, if you do you add a tiny pinch **(( and i mean under your fingernail amount, this CAN kill yrou shrimp & fish IF you does too much !! )) so you only do the smallest pinch, then just repeat with water changes inbetween , and only dose again IF to der see' the hydra, YOU can also take out the plant , rinse it in water and take yrou nails to pull it off and get it down the drain, I had ALOT and HUGE strands of it in my one gallon, BUT because thier were NO life in that tank, I was able to thro wout all rocks into my garden, and start anew with gravel from a diff established tank, and after throwly rinsing the sponge filter, and cking it for any hydra... Then putting the tank back up , I now have 3 drawf cajan crays in there all doing fine with NO hydra, this method is also used to treat planeria , and some other worms in overfed tanks ... HTH ~ and good luck . I would def try petlovers idea 1st, But if that does not get rid of them, search for this post I mentioned , it may also be under getting rid of planeria . Good luck . .
