Hi, I have 3 discus babies and one of them went through the same thing. It was at the point that I thought I would lose him, he went almost black in colour and would hide
I visited our local fish shop and they gave me garlic guard. When he wouldn't eat he refused everything except garlic soaked shrimp pellets then he came right. I did have to over feed a couple of times so he would get some and I dropped it in the front for the other fish then I would drop it where he was hiding.
I use garlic guard every day (advised by breeder) to prevent worms etc. Normally I use the cap and half fill it with garlic and put in about 8 pellets for about a minute, they dont like it if they completely fall apart. Then I put the whole lot in the tank, the other fish love it too.
He is now the biggest and strongest so I hope this helps, Good Luck.
