Observing the array of neon colours on display at the Two Oceans Aquarium, you’d be excused for thinking that some of the exotic fish, juvenile rays, sea anemones, coral fans and other underwater creatures that inhabit the exhibits are from another planet.

Such vivid, fluorescent colouring isn’t something we’re used to seeing in nature. But then again, we don’t spend much time underwater.

Neon colours highlight certain of the aquarium’s exhibits – especially those featuring crayfish, hagfish, anemones, giant clams and coral. The fluorescence is sometimes a display of pigmentation and colouring, sometimes enhanced by neon light, and other times it is an indication of biofluorescence, a natural phenomenon among around certain deep-sea species.

Biofluorescent animals absorb blue light and re-emit it as different colours, but in the absence of a yellow filter to block out the blue, the colours are invisible. Under a yellow filter, or for fish with a yellow intraocular lens, bioflourescent animals shine neon.

According to a recently published research report titled The Covert World of Fish Biofluorescence, it’s not just jellyfish and corals that can shine neon under water. Evidence now suggests that around 180 fish species do, too.

Read more about biofluorescence in National Geographic’s news article here, and check out some examples from the Aquarium below:

The Oceans of Contrast: Indian Ocean Gallery, filled with vibrantly coloured beauties from the warm Indian ocean, features the striking pencilled surgeon and clown triggerfish, along with neon-streaked wrasse and bright yellow butterflyfish

The spectacular tube anemones in the Oceans of Contrasts: Atlantic Ocean Gallery retract their tubes when disturbed

The revolting and yet intriguing hagfish, a species that dates back around 330-million years, also features in the Oceans of Contrast: Atlantic Ocean Gallery

Buzz, the resident brindle bass in the aquarium’s I&J Predator Exhibit, has magnificent yellow colouring

A close up of the clown triggerfish, showing the species’ iconic lips and spotted underbelly

The fluorescent coral reef exhibit is home to multi-coloured sea anemones and sea cucumbers, sinuous sea fans, coral, giant clams and sea urchins

The magnificent honeycomb moray eel may look like a snake, but it’s not. It's a fish

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