grouper acting strange

[gord 23]

I don't think my grouper is doing well. It's 6 inches long and hangs vertically in the corner much of the time. At times it's coloring is more washed out grey but quickly returns to the normal blue lines over black. I'm pretty sure the water quality is good in all ways. I test for salinity, phosphates. The tank is 75 gal. 10% water changes weekly. There are some corals in there that are doing well.
suggestions? thanks

 

[nereefpat]

What species? Got a picture?

Is it eating? What's it eating? How long have you had it?

 

[murphreef]

Sounds like a panther grouper?

They like to hang in the corners from my previous experience and they do turn a grey color at times to help conceal them.

I wouldn't worry if he is eating and otherwise swimming around.

 

[gord 23]

I don't think my grouper is doing well. It's 6 inches long and hangs vertically in the corner much of the time. At times it's coloring is more washed out grey but quickly returns to the normal blue lines over black. I'm pretty sure the water quality is good in all ways. I test for salinity, phosphates. The tank is 75 gal. 10% water changes weekly. There are some corals in there that are doing well.
suggestions? thanks

Blue Line Grouper. Had it a year and a half. Seems to be eating silver sides normally. But it doesn't swim around much and when it does it's more of a darting around.