Help! Longnose hawkfish not moving much day after Flatworm Exit

[KingNebTheGreat]

I did a flatworm exit treatment yesterday to knock down the population. Not a major population of flatworms but I don't think my sixline is big enough to eat the full size flatworms. Anyways I did the treatment yesterday, 40 drops and the tank is 54gal. Flatworms died, I siphoned as many as I could out (between 40 and 60 idk) but not all of them cause I saw more dead ones like an hour later. I ran my carbon and did a 25% water change 6 hours after the treatment with no issues in fish, corals, or snails. This morning I woke up to my longnose being perched under one of the tank's rocks and didn't think too much of it. However, I went to feed the tank about 30 minutes ago and he was and still is there under the rock. He is usually VERY excited to eat, but he wasn't today. I shot some mysis toward him and he didn't react until i moved my tongs close to him and he swam away from the tongs, ate like 5 mysis and went right back to the exact same spot. rinse and repeat a few times: move tongs, he swims away, then swims right back to exact same spot.
This is all very similar Eldritch_blast's thread, but there was not much advice on the flatworm exit aspect. im 99% sure it's something to do with the flatworm exit which is why i havent bothered with testing, but I can of course do that right away if it helps.

Longnose hawk fish lethargic, not eating

Hello everyone. I’ve had Karl since a couple weeks after tank finished is nitrogen cycle. They have always been one of my most gluttonous eaters, but past 2 days he has shown little interest in food. We feed primarily a smorgasbord of frozen with 3-4 different varieties a day. They are always...

www.reef2reef.com

What should I do? Should I get another 25% water change going or something else? should I just leave him and wait and see? I love him a lot and I would be absolutely devastated if I lost him.
Thank you so much!

 

[Subsea]

The best you can do is eliminate stress. For lack of options, consider a 25% water change.

 

[Mr. Mojo Rising]

Can you list the other fish in the tank? Hiding under a rock and not leaving for food - to me -sounds more like intimidation or bullying by other fish. It sounds like you have a relatively small number of flatworms, I've used it a couple of times with success so I'm a bit skeptical. I mean, why would toxins make the fish hide, are the other fish hiding? If the other fish are swimming around then to me its unlikely to affect only one fish.

 

[KingNebTheGreat]

2x clown fish, 1 springeri damsel, and 1 sixline. there was no aggression leading up to this apart from the damsel swimming around the general area and the sixline going around sometimes just picking at the rocks. if there was aggression it would have been from the damsel. if anything i think that the hawkfish and the sixline got along super well cause they would follow each other around and pick at the rocks together. and i don't mean follow each other in a hostile way from what i could tell. none of that matters anymore though because the hawkfish jumped out of the tank last night and passed away.