By Dr. Klaus M. Stiefel
Australia is a country of unusual wildlife. We have egg-laying mammals, outstandingly poisonous spiders and snakes, and urban parks and railway squares full of colorful parrots instead of drab pigeons. Underwater we may have the world’s most chilled-out fish, the red Indianfish (Pataecus fronto).
This fish is a member of the Pataecidae, or Australian prowfish family, which are distant relatives of the scorpionfishes. Their bodies expertly mimic the flat, red sponges found so abundantly in the waters around Sydney. Even the red Indianfish’s behavior mimics these sponges very well: it barely moves at all — if ever — just like a sponge. The (politically incorrect) name of the fish comes from its unusually high dorsal fin, which resembles a Native American headdress — which is more than a little bit confusing, since this Australian temperate-water fish is found nowhere near North America or India.
Given the red Indianfish’s considerable size — the one in the photograph is about a foot long – they are surprisingly hard to spot. This is the type fish an instructor would show to open-water students, just to receive clueless shrugs in return from the newbie divers who don’t understand why he’s pointing at a sponge so excitedly. Even when specifically setting out to find this fish, I must have overlooked it many times. I’ve only seen one of them, once, in about 100 dives in Bare Island, my diving backyard in Botany Bay near Sydney.
Australia’s considerable geographic isolation has allowed evolution to take different paths here than in other parts of the world. This is well known when it comes to land animals, such as the iconic kangaroos and koalas. But even underwater this continent has some unusual animals to offer, and the red Indianfish is one of these natural jewels.
