Flame Angel Sick?

I noticed my flame angel has been hiding near the back of the tank and only peaking out well when i went to feed he/she ate but its body is huge like it eat 50x today or somthing you know swollen or bloated?
What could that be? So i do somthing? I dont think he was able to eat sumthing that made it that big that is why i am worried!
Please let me know what i should do and what it could be!
Water is good now under 10 nitrates but ph is a little unstable 7.8-8.1 dont understand that one
75 gal nothing is picking on it, no spots or anything other signs just shy and fat! Thanks
No none of that just his body looks like he ate alot also i just noticed his color is a little light, i just feed the fish he still ate a tiny bit and is just hiding out acting shy, The breathing rate i would say went up just a tad not a lot, he can swin fine and still move around normally
Maybe he ate to much brine 4 days ago and has a stomic ack or sumthing?
If i took a pic you wont be able to tell anything really as its not that bad but way bigger then i seen on my fish , even my ocsars didnt get that big after eatting 20 gold fish lol
hey no more input anyone?
All i am reading is he prolly ate to much due to the signs i dont think its a diease or anything like that?
ill just keep a eye out but it would be nice to hear what you all got to say!!!
wow no input? Its been a week and he still looks the same hasent ate in 2days
ph 8.1
salt 1.023
ammonia 0
nitires 0
nitrates 15
temp 81


Sorry for not responding earlier! How long have you had this fish, was he a new purchase? What have you been feeding him besides brine? Brine offers little to no nutritional value and is often used by LFS's to make their fish look "plump"
sorry i forgot to anyways i had him for more then 2yrs i feed this flake that has garlic in it, I usally dont feed them brine maybe once a week if that, I feed the puffer frozen food and somtimes he gets a tiny bit of it but yes his diet is bad witch i just read about all that so i am now feeding lots of different food!
But he hasent eatten in about a wk and is still huge so i donno if he is going to make it!!!
no it hides all day but my puffer went though this like 3wks ago and when he did it was yellow and the flame would eat it so i am guess it got what the puffer had, we used melfix on the puffer witch is doing great now just the flame is doing very bad, my other 3 fish are fine as well!