Glowfish Species in Etharai | World Anvil


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Glowfish are an aquatic species native to the submerged caverns biome. They are small fish, a few centimetres in length. They are named after the soft glow that they emit, which provides light to the otherwise dark caverns of its habitat.

Basic Information


Glowfish are small creatures, with similarly small fins that are not particularly helpful in letting them navigate. They come in a wide range of colours, though are generally cooler-toned. Glowfish become more colourful and vibrant as they age, up until their death. A glowfish will continue to glow for up to a year after its death.
Glowfish have two eyes, which are positioned on the top of their heads. These eyes do not provide particularly good vision to the glowfish, evidenced by the fact that they are prone to constantly bumping into things. Glowfish have very few senses, and spend much of their time wandering around aimlessly.

Genetics and Reproduction

While glowfish are not built to be able to survive much, the only reason they have not gone extinct is their reproductive cycle. After a month of being alive, a glowfish will become fertile. They possess both male and female reproductive organs, and so can reproduce either sexually or asexually.
Glowfish will lay an immense number of eggs in their lifetimes, to compensate for their lack of survivability. On average, a glowfish will lay 3,000+ eggs in one laying cycle, and then promptly abandon them. Glowfish can have up to 300 laying cycles over the course of their lifetime, making it common for one glowfish to be able to lay 900,000 eggs during their short lives.
Glowfish eggs also glow, and are a good source of glow ink for harvesting.

Ecology and Habitats

The glowfish's preferred environment is deep underwater, in cold salt water. Glowfish are incapable of surviving outside of these environments, though not because they are physically unable to survive in unfamiliar environments, but because a glowfish will experience a heart attack at the shock of moving from one environment to a vastly different one.

Dietary Needs and Habits

Glowfish need very little food to sustain themselves, as they barely expend any energy. They are incredibly limited in what they can eat, and do not ever actively seek out food, so a high number of glowfish die of starvation, many shortly after being born.

Additional Information

Average Intelligence

Glowfish are incredibly unintelligent. They seem to not have the capacity to learn from their mistakes, and their memories are markedly short. In addition, they do not possess the drive to obtain food, something that is necessary for their survival. If not for their fast reproduction cycles, it is likely that the species would be extinct.
glowfish by notahumanhand
2-3 yrs.
Average Height
2-3 cm.
Average Weight
12 gm.
Average Length
3-6 cm.
Geographic Distribution
Related Materials

Glowfish Byproducts: Glow Ink

Glowfish produce a useful byproduct, known as glow ink. Made from the ink glands of the glowfish, this ink is readable in darker environments due to its pale colour and bright glow. It is popular for any signs or products meant to be used or read at night, and is used on many versions of safety vests.
Because of this, glowfish (and, more specifically, glowfish eggs) are farmed in many underwater cities fitting the environmental needs of glowfish. It is a highly useful export for these cities, who are able to receive important or useful surface items in return.



The glowfish feeds on microorganisms drifting in the water. They rely on the currents to feed them, and in still waters, they are at risk of death. They have no sense of hunger, and as an extention of this, do not have a drive to find food. A glowfish's survival is entirely dependent on luck.


One of the major predators of the glowfish is carnivorous algae. This algae is mostly stationary, but due to the glowfish's lack of environmental awareness, they often get lucky enough for the glowfish to accidentally swim into them and become trapped, to be dissolved by the algae.


The glowfish does have a little in the area of defense mechanisms. A glowfish's ink glands, which are what make it glow, are toxic to most species. The carnivorous algae, its only major predator, is one of the few organisms that can withstand these toxins, and most other creatures have learned to avoid eating them.

Cover image: Glowfish Group by notahumanhand


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Feb 17, 2024 22:59 by Aster Blackwell

Bahahahaha they're so stupid and pathetic. I love them so much.

Feb 18, 2024 03:38 by spleen

:D theyve gotta be a favourite of mine. i just love stupid animals so much theres something. endearing about them

Have a wonderful day!
Feb 18, 2024 14:39 by Aster Blackwell

Oh stupid animals are SO endearing. I love them too.