Calidus is Latin meaning fiery, spirited or rash. It can refer to:
Aircraft AutoGyro Calidus, a German autogyro design RotorSport UK Calidus, a British autogyro design
Animals Barbus calidus, a ray-finned fish species in the family Cyprinidae, commonly called the Clanwilliam Redfin Dardanus calidus, a species of hermit crab Falco peregrinus calidus, a species of Peregrine Falcon Rhodacaroides calidus, a mite in the family Ologamasidae