Clown fish acting strangely

[Randomlyahero]

I have two ocellarius clown and three other fish in my tank. Every fish is acting fine except for the female clown. She is laying on her side in a live rock cave. She will swim araound a bit and then back to her cave. She will completely stop and just lazely drift to one side and stay that way for a few minutes. her other half isn't hanging around her as much they were never seen to far apart until recently. Is she dieng? She is around three years old and apears healthy on the outside could it just be old age? My wife said she saw a white string coming from the fish which I assumed was just poop but we contacted our lfs and they recommended dosing with prazipro and we did 3 days ago.her behaviour has not changed. Any help or insight would be appreciated ice had these clowns since they were around dime size and would hate to loose one

 

[Randomlyahero]

Also she is opening and closing her mouth rapidly like it's struggling to breath

 

[Harrhugh]

Don't know. Hopefully she is just fanning her eggs.

 

[Randomlyahero]

She died last night. Stopped moving all together and just laid on her side I moved her out of the tank and she died about an hour later. She lost all of her color towards the end and that was the last step I guess.