I used a all-in-one fish med (for "gill flukes, anchor worms, ich, and fungal diseases" ) . I did not pay attention to the main ingrediant, but I know it was not the same as Panacur (it started with "M" ) . I doubled the dose (two packs per 10 gallons) and waited 24 hrs.
It's been four days now and I can't find any survivors, and none of my fish or snails seemed bothered. Hopefully this got them, but I'm still not confident enough to say they are gone for good. If I can't find any for a couple more weeks, I'll consider them all dead.
This treatment cost me $13.50 (the whole contents of the box) for a 50 gal tank. Is that about what the Panacur would have run me? Is two weeks long enough to not see any and consider the hydra "gone" ?
-Dave