Newquay’s Blue Reef Aquarium is showcasing a bizarre apple-shaped sea cucumber from Australia in a new toxic display.

The sea apple is a type of sea cucumber which is also related to urchins and starfish.

It gets its name from its apple-shaped appearance and is brightly coloured to alert would-be predators to its deadly toxins.

Blue Reef curator Matt Slater said: “It’s the first time we have been able to put sea apples on display and they really are extremely unusual creatures.

“We’ve had to keep them in their own display away from the other fish as they are extremely dangerous and contain highly dangerous toxins within their body tissues.

“In addition to their toxicity, the sea apples also possess the ability to expel their internal organs to distract predators.

“One final trick they use is to consume large amounts of surrounding seawater to swell to nearly double their original size. This enables them to be moved to a new area by water currents much more quickly than they could walk,” he added.

The bodies and tentacles of sea apples come in many different colourings. The Australian species has a primarily purple body, red feet, and purple and white tentacles.

The sea apple feeds primarily on plankton, which it filters from the water with its tentacles. They alternately bring each tentacle to its mouth, feeding itself from the captured plankton.

Sea apples usually feed at night, when their delicate tentacles are less at risk from predators.

They share their new display with a colony of their close relative and fellow echinoderm the candy sea cucumber.

“It’s quite unusual to have an aquarium display without any fish in it but these are such bizarre creatures that we felt they deserved it,” added Matt.

“Echinoderms like the sea apples are thought to be most closely related to the early vertebrates so in some ways they’re actually our distant evolutionary ancestors!”