 Several sources also report sightings of filter feeders like manta rays and whale sharks, scavengers such as barracudas though fishing is said to have made their appearance less frequent.Richelieu Rock is also well known for its large variety of small and rare marine critters, such as sea horses, frogfish, harlequin shrimp, pineapplefish, orang utang crab and several other species of crabs and shrimp.Dive Richelieu rock with Richelieu Rock.