I´m very positive of it being poop and not a regurge. I didnt take a picture, but i was like a bird poop, with urates and undefined guts. He was off feed for the last month, and that was his first rat. But then again, all the others go off feed and never do that. I do have a T-stat and a thermometer, it´s a rack with ten balls, all great.
Parasites maybe?
Last december he was 150gms, now he´s 600 gms, wich means he´s growing ok. I´m lost, I think i´ll just keep an eye on him hoping it was a one time thing.