Morning @Blue Ridge Reef
I only have experience with "No Planaria" as fenbendazole is considered a controlled drug here in SG and hence impossible to get!
I have used "No Planaria" a couple of times now in shrimp tanks with Amazonia soil to get rid of hydra (thankfully not planaria.... yet!). I found that the "No Planaria" had zero noticeable effect on any of my shrimp, small chilli rasbora fish, Christmas moss, salvinia, or the many Malaysian trumpet snails in the tank. The first time I treated, I removed all the MTS I could first. However after treating, I noticed that the tank still had many many many tiny baby MTS in it. I assumed they were doomed (but I had parents safe so not too big issue), but actually all the baby snails were just fine, both during treatment and ever since. No noticeable effects in the tank during or anytime after treatment. I know MTS are at the more robust end of the snail lineup, but I figure 1-2mm size babies would still have been sensitive to anything 'toxic' to snails in general.
Anyway, my full write-up of my "No Planaria" vs hydra experience is here if it helps:
I found that a single dose was enough to kill hydra (the day 2 50% dose and day 3 25% dose were not needed). I used the full recommended day 1 dose in my RCS tank and hydra fell from the glass within an hour, and I tried a lower 70% dose in my CRS tank and found that they hydra still died, but it took 10-12 hours. So I think the recommended dose is about on the mark; it certainly doesn't seem to be excessive, at least when it comes to treating hydra, as effectiveness dropped noticeably from 100 to 70% dose. Maybe 50% dose might still work too, but I think I'll use a single 100% recommended (day 1) dose in the future if needed as this seemed well tolerated by everyone.
If you are able to treat separate tanks with Panancur and "No Planaria" and compare, then that would be great to know for future reference! Interested to know how you get on anyway. My LFS seems to have a perpetual planaria issue so I fear it is only time before I'm in the same predicament.
Regards, James =]