blood is so cool
There’s hemoglobin - the stuff in you humans
There’s hemocyanin (blue) - a variant for mollusks and crustaceans
There’s chlorocruorin (green) - leeches and worms
There’s hemerythrin (purple) - certain bristle worms
There’s even an antarctic fish with CLEAR BLOOD because oxygen dissolves readily into the water around them, a sufficient amount for them to sustain their low metabolisms
There’s also terrestrial hemolymph which is the goop in insects and arachnids that secondarily evolved to lack hemocyanin due to size
I just realized this must sound weird coming from my url