Can someone tell me if the blood in the veins is blue or red?

Dark red: The color of blood is related to the amount of oxygen in the blood - the more oxygen in the blood, the more red it appears. If there is less oxygen in the blood, it will appear darker - but still a shade of red. Veins carry less oxygen than arteries. So, blood inside a vein is often a dark red/maroon color. On the surface of the skin, veins can look blue due to overlying skin pigmentation.