I can tell you that the ARTC is most definitely the reason he was chewed up. They do the majority of their destruction at night. His whiskers will grow back, but only if there isn't anything still chewing on them. I would recommend keeping them at normal tropical temperatures like 76-82F. Did the place you got him from mention what they were feeding it? If not you have two options, try to get him eating prepared foods(I would recommend frozen shrimp, the kind you or I would eat, thaw it out for a minute in a cup of water from the tank, and then break it into small pieces. You should take the tail off, or save a step and buy it deveined and with the tail already off. You can buy the cooked or uncooked kind. Uncooked is generally accepted more readily.) Option 2: live feeders like rosey red minnows, usually easily eaten, but then you run the risk of exposing him to interal parasites, plus if there is something in the tank that is faster than him he won't get anything to eat.
I would try the shrimp myself. Delicious and nutricious as they say. GL and let's see some pic's.
