Freshwater moray eel white blotches

[Fishlover123]

I bought my freshwater eel about 4 days ago. He looked fine when I bought him but after a couple days he started getting a white blotch along the top of his body now he doesn't eat and he said that the bottom of the tank all the time and he also keeps leaning over on his side but then we'll fix himself again. I've looked all over Google to find out what is wrong with him and I can't find an answer please