Your maroon clown
may also be suffering from a parasite. I would check into the possibily of C. irritans
or more likely Brooklynella hostillis
. Both of which must be treated in a seperate QT
along with any other fish in residence.
If this is just a blockage, slightly soften peas mixed with the brine should help clear it unless it's and internal infection. In that case you may need to QT
and treat with an antibiotic. I would start off with the peas and a few large water changes with well aged SW
first providing you have eliminated the possibility of disease or parasite.
I would also try finding some different foods for the fish other than brine. It offers little or nothing in the way of nutrition. Blender mush, mysis, fortified flakes and the use of a good liq marine vitamin would be good.