Lovely baby, I am so glad you found him /her .
Just keep an eye out for infection, fungus....I would say Chief_Waterchanger has it right (no question), but I would go one further and say to test your water and make sure you do enough changes to keep it down around 5 Nitrate until he's healed. A mixture of vegi wafer and a good protein food will help him heal.
What is his normal diet?
He looks MUCH better than the first Gold Nugget I ever got. He jumped out, and I didn't find him for two days, upside down in the silverware container in the dishwasher! Dry and dead...
You were lucky.