Royal Grama w/ large gash/white chunk

[reef dude]

Ok, i have had my reef up for about 4 and a half months and have 2 perculas, 3 firefish gobies, yellow wrasse, royal grama, pink tip haitian, and one feather duster.
Today however i noticed a large gash on one side of my royal grama. from the side view, it looks as if it almost swam into a sharp piece of rock and cut a chunk off his body. when i look at it head to head, it has a white color, and when i look at the wound from the side, it has a brownish pink tint. There is no sign of any external fungus or bacteria, just looks like he got a beating. I also notice that when he swims around the tank, he opens his mouth EXTREMELY WIDE which i have never seen it do.
****by the way, i have NO experience with fish diseases or wounds and i dont even know what to type in as a keyword to do some research on it. I hope i described it good enough!

 

[beth]

Well, who is the aggressor? That is the important thing to find out, because you can bet it will continue to be a problem.
Unless you have a hospital tank, and you can isolate the fish in there, there is not much you can do.

 

[reef dude]

well im not so sure its being picked on. the only action i see are my 2 percs going after eachother. However, ever since i noticed the marking on the royal grama's gill, i noticed that the more dominant percula is nowhere to be found....

 

[reef dude]

i just found out why my true percula clown was missing. He jumped ship. I found him on the floor behind the tank, dry as can be. Theres a very small area up by the pre-filter box where he must have jumped, ive seen him swim there all the time. The good thing is, i saw no marks on his body which means nobody was getting picked on, just a fluke.
As for my royal grama, should i just let him be???? and medicine or quarantine suggested??

 

[beth]

Well, percs are not known as jumpers. What are your water readings?
Also, could you have an invert predator in the tank, like a mantis shrimp?

 

[staticx1134]

the same thing happend to me with my gramma, he hid under a rock kinda laying down and the next morning i found him dead ( im getting teary-eyed) i honestly think that my shrimp wounded him cause all i had in my tank was 2 false perculas.....

 

[reef dude]

yes i have 3 peppermint shrimp in my tank, they never come out from the rocks though