Sick Anthias

[SuncrestReef]

I've had two anthias in my 88 gallon display tank for over 6 months and they've been healthy and active. Yesterday, the larger anthias began acting oddly, swimming vertically and twitching side to side. Today, he's just laying nearly motionless on the sand at the back of the tank. Still breathing normally, and no visible spots or other symptoms. During feeding he did eat, but just swimming very slowly and erratically. All my other fish including the smaller anthias seem fine.

All water parameters are normal, and I test frequently.

Any ideas what would cause this, and any suggestions for treatment?

Video from yesterday:

Photo today:

 

[Frtdrmrose7]

The usual first question, have you added anything to the tank recently?
Have you observed any aggression towards this one from the others?

 

[SuncrestReef]

The usual first question, have you added anything to the tank recently?
Have you observed any aggression towards this one from the others?

The most recent addition was a new diamond goby over a month ago, but I had the goby in QT for a month prior to moving to the display tank.

The sick anthias had been the most aggressive fish in my tank up until now. None of the other fish mess with him.

 

[ngoodermuth]

I almost wonder if it’s neurological... maybe he swam into something?

I’ve never seen behavior quite like that due to a parasite, though if you can catch one of your other fish to check for flukes could at least rule that out. I’m not sure I would dip this guy unnecessarily

@BigG @HotRocks @4FordFamily... any ideas?

 

[HotRocks]

This can be one of two things. Could be a spinal injury. Could also be a symptom of internal flagellates. If the latter is the more likely of the two but I would think you'd have seen white stringy poop by now.