Internal parasites? [Flowerhorn]

[SuperVeil]

Hello you all guys!

I'm seeing for weeks a lot of little white worms in the water of my tank, they are not on the glasses, they are just free swimming...

I didn't gave it importance because my flowerhorn looks healthy as always but yesterday I saw white poop... it was exactly like this:

(photo is not mine)


It wasn't transparent or semitransparent poop, it was just solid white.

At this moment all my alarms were activated, I thought about internal parasites! Maybe those white worms that I was looking free swimming for weeks ago are from his intestine :/

Today I gave him drontal on the food (praziquantel/pyrantel pamoate/febantel) Broad Spectrum Anthelmintic) I hope this kill the worms in his intertine but I am thinking about those worms that are swimming free on the water... ¿How could I kill them?

Here I post you a video of those worms that I am talking about, this video is mine:
Watch it on HD to appreciate the worms moving
https://www.youtube.com/watch?v=J-wUaR4JJsY

I have also ordered CLEAR med, but it won't arrive me untill 15-20 days...

Thank you in advance guys!