Banggai Cardinal struggling to swim

[BurtMacklin]

One of my 3 Banggai Cardinals in sliding along the sand bed, has been spitting food out (frozen mysis/brine), and won't touch pellets or flakes. He's been in my 65 gallon for about 2 weeks. My two phantom black Clown Fish were quarantined by me, the cardinals were purchased pre-quarantined from Dr. Reef. Posted a video. Let me know if anyone has any ideas what might be wrong.

Temp: 79
Ammonia: 0
Nitrate: 7
pH: 8.15
KH: 7.9
Mg: 1185
Ca: 390
PO4: 0.25

 

[vetteguy53081]

May be post aggression or bladder issue not uncommon with cardinals. Swim bladder issue responds well with use of erhromyacin (mardel maracyn 2). As an alternate, Melafix should also work)

 

[BurtMacklin]

May be post aggression or bladder issue not uncommon with cardinals. Swim bladder issue responds well with use of erhromyacin (mardel maracyn 2). As an alternate, Melafix should also work)

The heavy breathing is worrying me. Unlikely aggression. Everyone has been getting along great. He's off swimming higher now after I tried to feed him mysis with a turkey baster. Didn't even try for food today. He seems to be able to swim if he wants to, but breathing hard, very low energy, and getting pushed around a lot by the current.

 

[BurtMacklin]

So I moved him to a hospital tank and treated with antibiotics, but he declined quickly and passed. I put him in tap water later to check for flukes and this one small white bit came part way out of his gills on just one side. Is this a gill fluke?

 

[Jay Hemdal]

Can’t really see clearly, but for flukes to have been the cause of death, you would see dozens of them. Some gill flukes are too small to see without a microscope.
Jay