Octopus blood is clear due presence of cooper blood called hemocyanin helps them live in the extremely cold and low oxygen environment.
Scorpions contain blue blood due to high levels of hemocyanin in their blood which helps them live in low oxygen environments.
Horseshoe Crab's blood is blue due to hemocyanin floating freely in low oxygen levels.
Spiders blood color is pale yellow, blue, or clear due to the presence of hemocyanin which helps to live easily in low-oxygen environments.
They have yellowish blood due to holothurin, which helps them defend against predators.
Peanut Worms contain purple blood due to hemovanadin which helps them transport oxygen in a burrowing environment.
Brachiopods contain clear blood or black blood due to hemocyanin to live efficiently in low-oxygen environments.