Gill flukes?

My platies have been flashing. I've seen other tank members flash before, but very infrequently and no fish ever seemed to get worse. Like, I would notice a cory flash against the substrate one night and then see no other flashing until 2 weeks later I saw a pearl gourami flash once. But over the past couple of days the platies have been doing it repeatedly. One of them gave birth this week and now she spends a lot of time up near the top, so I'm worried. I picked up some prazipro as I suspect gill flukes, since they are really targeting the flashing to the gill area.

I'm pretty nervous to dose my tank but from what I've read this is one of the milder medications and SHOULD be safe for my inverts (shrimp + snails) and biofilter (do you all agree?). I imagine if the platies have a parasite then all or some of the others must have it to some degree and/or it's circulating through the tank. Am I right to think I should dose the whole tank? Or just remove platies?

Tank stats:
40B, stock list in sig below
0 ammonia (tested yesterday)
0 nitrites
15 ppm nitrates
3 KH
6 GH
7.8 pH
tank runs at 76-78 F
Last WC yesterday, 40%, do weekly WC or more often of 25-50%

TIA

Well, I dosed the whole tank to 2.5 ppm. So far everyone seems fine, fingers crossed I'm right about the cause of their flashing and this will help the platies. They don't seem to have any other symptoms besides flashing and hanging up at the top but one of them has redder gills than the other. I'm not experienced enough to know if they look irritated or not. I'll keep updating just in case it's useful to anyone else.

Thanks, good to know!

It might be wishful thinking but the platies seem a bit better.

Well, the platies perked up completely this week, and the other female (I have 2 F) gave birth as well but with much less of a "bed rest". No other fish have been observed flashing the entire week either, which might not mean too much since they were not flashing regularly before but at least no news is good news! The platies had gotten so they were flashing several times an hour, and they have stopped completely, so I think that I was probably right about the flukes.

I did a 50% WC on Friday and re-dosed to get any newly hatched fluke larvae. Again, as Subrosa said I see absolutely no effects to any fish, shrimp, snails or plants. Actually saw a healthy, active platy fry in the tank during the big WC- my first!! I have a hungry community apparently so I have always been able to tell when any LBs I have in the tank give birth but I've never seen a fry. But anyway, in case this is useful for someone later, the prazipro even seems totally safe for fry as that one must have been born before I dosed or while there were stil meds in the water. No discoloration of my silicone, only effect really is a slight smell of cherries for about 36 hours after adding the meds.