I got a motoro in with the same kind of burns on its belly but mine was skin and bones. It took about 2 weeks for the red to fully go away. Best thing to do is keep changing about half of the water in that 30 gallon daily. I had mine in a 30 gallon Q tank for about a month before moving it to the main tank. As far as food, they will not be able to resist ghost shrimp. If you get them to eat that then try small pieces of earthworm.