Sick Fish, Please Help!!!

[BigE]

I have an Aurgia Butterfly that I've had for about 3 months that is swimming at the bottom of the tank staying relatively in one spot. He's also turned a darker shade like he normally does when the lights go out. He' sabout 3 inches long, fins look good, no spots or any outward phisical signs other than the darkening. 2 other fish in the tank are fine and aren't picking or bothering the butterfly. He also isn't eating.
Any input on what might be causing this and how I can help him would be much appreciated.
Water temp is 82 and been very stable
salinity is at 1.025
skimmer runs 24/7
80 gallon tank with 10 gallon refugium

[MontanaRocknReefer]

How is your ammonia level? Says this fish is very sensitive to it!!

[BigE]

Unfortunately I'm not sure. I don't have any tests right now. I don't think it could be very high if detectable at all.
I just did a 5 gallon water change and will do another as soon as the water is ready.
I also turned off the skimmer since higher O2 levels increase PH which also increases the toxicity of amonia. Is this good logic?

He's been looking worse over the past hour, laying on the bottom although as I'm typing this he just perked up and is moving his fins more but still staying in one spot.

[Alice]

Has he been eating since you've had him?

[BigE]

Yes, he has been eating flake and frozen Since about 2 days after I got him. He also grazes on the rocks all day eating the pods. About 2 days ago I noticed he wasn't eating as much as usual. He would only eat a few peices.

[BigE]

I have a feeling he may be blind... watching him swim he doesn't seem to be aware of whats going on around him, doesn't move his eyes and has run into the tank walls.
Are there any deseases that might cause blindness?

[Alice]

Have you had any rock falls in your tank which may have injured him? It could also be a result of cyanide capture but I'm not sure if the timeline is right. Horge, JennM or Spanky would probably be able to tell you. Maybe one of them will chime in tomorrow.

[BigE]

Nope, no rock falls. The tank has been pretty stable for quite a while. I haven't made any changes to the tank the entire time I've had the fish

Things have gotten really bad now. He's lying on the bottom most of the time and the other 2 fish are starting to pick at him. After they bite him 2 or 3 times he starts swimming around doing cartwheels, bumping into the rocks and tank walls.

I was looking into this guy for like 2 months before I got him, talk about a bummer.

[Alice]

Do you have a hospital tank you can move him to? Things sound pretty grim but he won't have a chance if the other fish keep after him.

I'm sorry it's not turning out well.

Alice

[Casey]

sorry to say but hes a goner sounds like cyanide to me.

[MontanaRocknReefer]

One of the big problems in this hobby is collecting fish and not knowing what the collection practice used in obtaining this fish! I try to find out from the LFS owner but even they are not always sure or misled as well! Sorry to hear of the health of the fish.

[BigE]

Well, he didn't make it through the night.
I got the fish from Dr. Fosters and Smith who "verified" for me that the fish is net caught which is probably just their standard issue answer no matter what fish or supplier they're dealing with.
Thank you everyone for your help.