Not all animals have red blood. In fact, the blood in animals can have other colors like blue, green, yellow, purple, and even white!
Purple blood color is due to the protein known as Hemerythrin.
Oxidized copper in the blood give the blood a blue color.
Few Octopus Species
Biliverdin is the cause of the green color blood.
The yellow colour is the cause by the metal known as vanadium.
It completely lacks the proteins hemoglobin and hemocyanin. That’s the reason why they don’t have any color.