I can't really see much in that picture. Too fuzzy for my old eyes.
Is it a "blood red" or more of a rusty red? It could just possibly be one of his colors. I've had some zebras with an orange color tinge. If it is a red as in blood vessels I would worry about a septicemia but if you think it's just it's colors coming in I would just keep a close eye on it and keep up on water changes just to be safe.