Animals Notes on anime, games & creatures

Why Do Fish Glow in the Dark: Science and the RPG Glitch Aesthetic

Off the coast of Eden, on the southern NSW shoreline, divers sometimes report flickering sparks in the water column on summer nights. The local spectacle is usually the sponge gardens and the annual whale migration, but the particles of light have nothing to do with stars. They come from tiny marine organisms using the same trick a hatchetfish uses almost half a kilometre below the surface: a chemical reaction that produces cold light without heat. Australia sits beside one of the most diverse marine environments on the planet, and bioluminescence is part of the deep-water cast whether divers ever see it directly or not.

The phenomenon happens when a molecule called luciferin meets an enzyme called luciferase in the presence of oxygen. The reaction releases photons, and because almost all of the energy leaves as light instead of heat, the fish stays efficient in cold, food-poor waters. Different species mix their own recipe, and some even borrow luminous bacteria from the sea to glow on demand. The result looks like the deep ocean has switched on a nightlight.

That visual has been borrowed so often by games and online art that it now feels like a default setting for anything calling itself eerie or futuristic. The crossover between marine biology and the glitchy RPG aesthetic runs deeper than decoration. Both worlds lean on contrast, points of light floating in darkness, and the suggestion that something larger is hiding just out of view. Knowing the real science makes the borrowed imagery land harder, especially when players and modders keep coming back to it.

The chemistry behind the glow

Luciferin is not a single substance. It is a class of molecules, and each species of glowing fish tends to use a slightly different version. When it oxidises, often with the help of luciferase and a little oxygen, it emits visible light. Marine biologists in Australian labs, including teams linked to CSIRO, have mapped several variants found in deep-water species that swim not far from the continental shelf.

The colour is rarely random either. Many deep-water fish glow blue-green because those wavelengths travel furthest through seawater. A fish drifting in the mesopelagic zone benefits from being just bright enough to vanish into the faint downwelling sunlight rather than stand out as a silhouette. It is camouflage written in chemistry, and it is ancient. Researchers studying fragments of fossilised photophores suggest glow organs have been in use for more than a hundred million years, well before anything bipedal ever wondered about them.

Built-in lanterns on living fish

Glow does not just happen. It is produced by specialised organs called photophores, which sit under the skin and sometimes connect to reflective cups that act like built-in mirrors. Some species can rotate the organ, switch it off, or pulse it like a slow heartbeat. The level of control is what separates a glowing body from a working signal system.

Photophores appear in unexpected places. Certain anglerfish carry them dangling from a rod above the head. Some ponyfish wear them around the throat. Hatchetfish have rows along the belly, while the cookiecutter shark, found in warmer waters around Australia, lights up around its throat and underside. The arrangement is rarely accidental. Each pattern serves a particular survival task, and the visual result, especially under ultraviolet dive lights, looks unsettlingly like circuitry drawn across a creature's body.

Evolution wrote the first pixel art

Three pressures seem to shape most bioluminescent strategies. Counter-illumination hides a fish from anything looking up from below by matching the faint light above. A lure turns a fish into a hunter, attracting prey close enough to be inhaled. And a signal identifies the fish to mates or warns rivals away. Each use creates its own distinct pattern of glow, almost like a sprite in an old game.

What makes the aesthetic feel glitchy is the irregularity. Real photophores are not placed in tidy grids. They cluster, scatter, and trail along fins like corrupted pixels on an old CRT monitor. Game artists who copy the look inadvertently reproduce the same visual noise nature has been producing for millions of years. It is the kind of detail that modders adore when building their own creatures, and it is also why the underwater sections of older RPGs feel off in a way players describe without quite knowing why.

Glowing down under

Australian waters hide an unusual amount of bioluminescent life because the eastern coastline drops quickly into deep, dark habitat. Lanternfish, probably the most abundant vertebrates on Earth, migrate nightly toward the surface and have been recorded in massive numbers along the East Australian Current. Trawl surveys off Tasmania and Victoria regularly pull up myctophids covered in photophores, and the same surveys support catch limits set under federal fisheries legislation around the southern seaboard.

Recreational fishers in places like Port Phillip Bay rarely see glowing fish directly, but they are downstream of the same food web. Tasmanian glow-worm caves, although technically an insect trick rather than a fish one, are a popular stop for families working out kids choosing weekend activities around Hobart during the cooler months. Marine tourism operators near Cairns and Sydney sometimes run night snorkels during plankton blooms when flickers outline any swimmer who disturbs the water.

A few bioluminescent creatures worth knowing if you are exploring Australian shores:

Pixels, mods, and the modder's lure

The RPG glitch aesthetic borrows the idea of a creature that should not work but somehow does. Coral reef lighting in indie games often looks wrong in the best possible way, with patches of pink and green smeared across models that were supposed to be realistic fish. Texture artists call the effect "broken shader". Marine biologists would call it a successful camouflage strategy. Both fields have spent decades refining something the eye reads as natural mistake, and players have learned to treat both as signs of a world with depth.

Cyberpunk visual design leans hard into the same vocabulary. Neon highlights on dark bodies, soft haloes, and the suggestion of an internal battery all start to feel standard. A fish with photophores is, in a quiet way, the original source material for that template. Designers rarely copy a fish directly, but the urge to put lights inside a creature seems almost universal across game genres, even when the team does not consciously know why.

When games borrow the ocean

A handful of titles lean into the look harder than most. Subnautica uses glowing fish to mark danger zones while players explore deeper biomes. Sea of Stars leans on the same cold blue palette. The MMO Final Fantasy XIV has enemies whose silhouettes copy real counter-illumination patterns almost frame by frame. None of these choices feel accidental, and the artists involved usually cite nature documentaries as part of their reference pile.

The connection works because both sides are chasing the same feeling. A faint glow against a dark background sets a mood that bright colours cannot. Whether the source is a four-centimetre lanternfish or a hand-drawn sprite, the visual trick remains the same. Light in the deep has always been a story, and games keep retelling it in their own dialect.

A short player-made list of where the look shows up in gaming: