Another rare creature has been pulled from the ocean, this time a two-mouthed fish, weeks after the frill shark and the megamouth made headlines around the world.

Fisherman Garry Warrick caught the deformed bream in a net at Lake Bonney in the Riverland region of South Australia.

“Both mouths are actually joined together,” he told the ABC. “The top one opens and closes but the bottom one looks permanently open.”

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Bream was apparently able to feed itself normally.

To the angler’s surprise, the fish was alive when caught, which means its unusual mouths must have been in working order.

Over his three decades in the industry, Mr Warrick has seen a few other deformed catches, including a carp with a dolphin-shaped head.

“I normally pack them for cray bait and fertiliser but this one I put in the freezer,” Mr Warrick said.

“I hadn’t really told anyone about it other than my wife, and she said you might as well put the photos online.”

One theory is that fish deformities of this nature are caused by agricultural chemicals.

Thousands of two-headed fish were reportedly born in a Queensland hatchery in 2010, which was been blamed on chemical sprays used by neighbouring farmers.

Birth defects in animals can also occur naturally as a result of genetic disorders.