My Golden Algea Eater Is Sick. Help :(

[ChaseO]

My golden algae eater fish is sick. I have removed him from the tank. Now he is in a smaller half gallon tank. I have added MELFIX, and API FRESH WATER AQUARIUM SALT. He has red vein like stripes throughout his body, And he is very lethargic. He has a bloated stomach and is very Lethargic. WHAT IS WRONG WITH HIM. WHAT CAN I DO TO SAVE HIM???
THANK YOU VERY MUCH FOR YOUR HELP!

 

[Shelster]

Have you got any pics?