There are little black specks in my dog's fur. What is it?

I have a toy poodle and I just began noticing some black specks tangled in his fur. I don't think they're fleas since they don't move but I don't think they're flea dirt either since it doesn't turn red in contact with water. Does it immediately turn red in contact with water? So what is it? Could it just be dirt? I've gotten rid of most of it, but there is still some left occasionally. If it is fleas/flea dirt, how can I get rid of it? Thank you.