How soon and best practices before following other meds with prazipro?

[SWilson]

I've had 3 pea puffers in a planted 55 gallon for about two weeks (they are the only ones in the tank).  Within the first 24 hours, a fourth one I had originally bought died (declined really quickly in the span of about 12 hours, and just before dying looked like he had some fungus or something around its mouth).  As a precaution, I dosed the whole tank with maracyn, and changed out 15 gallons on day 6.  

Around that time, I then saw one of the most horrifying things I have ever seen in one of the 3 puffers.  When he was trying to eat, a thin white worm looking thing shot out of his mouth, and then retracted.  Seriously, like something out of an alien movie.  It (the worm) kept doing that.  The next day he also had two long thing worm looking things coming out of his anus, plus the one coming out of his mouth.  I hit the whole tank with paracleanse, called the store manager where I got them, who swore up and down that he had spent 2 months deworming them before putting them out on the floor, and suggesting that I stop feeding live black worms (which I also got at his store, btw).   

Since the Paracleanse, I have not seen the worms coming out of the anus, and I can still sometimes see the worm coming out of the mouth, but it's much smaller/shorter than before the meds.  I want to try to get a video of this but unsuccessful so far.  I have not seen this in any of the other puffers and this guy with the alien worm is eating well, active, and is actually the fattest one of the bunch.

One round of paracleanse is done, another 15 gallon water change was yesterday.   

I'm thinking I'll try Prazipro next.  Any harm in still continuing to dose the whole tank? (I'd rather minimize the need to move puffers since they shouldn't be brought out of water)  Anything I should do before starting the prazipro? I know it's the same as one of the ingredients in paracleanse, just higher concentration.  I'll start with the dose recommended on the bottle - or should I start with a lower dose?  Should I wait for a certain period of time before starting the Prazipro?  Should I change more water to dilute out the remaining paracleanse before starting?    

i have tried searching this forum for "prazi" before posting, apologies if I've missed the answer out there already. 

[SWilson]

Just putting this here in case it’s helpful to anyone in the future. Giving myself the classic advice for newbies, since the fish was otherwise appearing in good condition - give things time. 
I haven’t seen visual evidence of the worm in a couple days. So I’m just continuing to monitor. After a couple weeks and enough water changes to clear out most of the old paracleanse. I’ll do a second round with prazipro as a preventative and in case there is a second generation of worms. 
If things were more dire and I needed to act fast I would have probably changed as much water as possible (with puffers I probably would just do 50%) and run carbon in the filter for 24 hours to remove the remaining medicine before dosing with the next kind of medicine. 

[Colu]

I would do I  water change  use carbon after 24 h you it will be ok to treat with prazipro