I agree with Reefman. Looks like red cyano. ( the little bubble on the right of the photo is too) just blow it off. Do you have a lot of this in the tank?
3 or 4 spots of it? Just keep an eye on it as it can spread fast if conditions are right. If it does, you need to take a look at your nutrient levels/ export mechanisms and perhaps increase your flow and reduce your photo period. A little bit is quite normal.