Marblefish Species in Etharai | World Anvil


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Marblefish are a small fish species native to the whirlpool reefs. They have transparent skin, and eat the pearls of rainbow clams.

Basic Information


Marblefish are small creatures, reaching a maximum of a single inch long. They have transparent skin and mostly transparent organs, allowing them to blend in to their environments... sometimes. Most of the time, however, marblefish are in the middle of digesting their food, which makes them bright, colourful, and shiny creatures.

Ecology and Habitats

Marblefish are native to the whirlpool reefs, and are incredibly picky about their environment. In water with a slightly lower or slightly higher salt content than their natural habitat, they quickly become sick and die. In slightly warmer or colder temperature water than their natural habitat, they will freeze or overheat, and typically die.

Dietary Needs and Habits

Marblefish subsist on the pearls made by rainbow clams. These pearls are only slightly smaller than the marblefish themselves, and can barely fit into their mouths, despite them being able to unhinge their jaw to almost the full width of their body. It takes them a few weeks to digest this pearl, during which the pearl is clearly visible through the fish's skin, and gives them a shiny, marble-like appearance from which they get their name.
To obtain these pearls, the fish will look for rainbow clams and, when found, swim near the clam and cause ripples in the water that will cause the clam to open. When it does, the fish will dart in and grab the pearl, darting out just as quickly.
The clams do not mind the fish, as it prevents their pearls from becoming too big and not fitting within their shells.


Marblefish move together in schools of around 20-30 fish, and scatter at any sign of danger. They move in these schools for protection in numbers, and scattering allows them to confuse their predators, allowing many to escape even if all do not. They are very panicky fish, however, scattering at any sudden changes in environment, including shadows, ripples in the water, and falling rocks.
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Geographic Distribution


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Dec 11, 2023 00:41 by Dr Emily Vair-Turnbull

I love that they eat pearls and that it makes them shimmery whilst they are digesting.   As someone with tanks, the ecology and habitats section is a 'realities of fishkeeping' moment, haha.

Emy x   Etrea | Vazdimet
Dec 11, 2023 00:59 by spleen

yeah, keeping these guys in a tank might be a little bit difficult xD

Have a wonderful day!
Feb 11, 2024 16:48 by Aster Blackwell

The image of a transparent little fish with a big ol pearl in its stomach is so hilarious to me