Glass catfish
A small, transparent freshwater catfish from Thailand.
Kryptopterus vitreolus is a tiny, see-through catfish native to southern Thailand. It became a distinct species in scientific records only in 2013, separating it from similar larger relatives. This fish is popular in home aquariums for its unique appearance and social behaviour, though most specimens are caught in the wild rather than bred in captivity.
- Body is transparent due to lack of scales and pigment
- Scientifically distinguished as a unique species in 2013
- Organs cluster near head, allowing heart to be seen
- Native to rivers in southern Thailand
- Reacts to electromagnetic fields via special protein
What it is
This small catfish has a body that is almost entirely clear. It lacks scales and skin pigment, which allows light to pass through its muscles. The internal organs are clustered near the head, so a viewer can sometimes see the heart beating with magnification. Two long sensory barbels extend from its mouth. When light hits the fish at specific angles, its collagen structure creates a faint rainbow shimmer. If the fish becomes sick or dies, its tissues turn a cloudy white colour.
Where it lives
The species lives in fresh water within Thailand. Its range covers rivers and streams south of the Isthmus of Kra that flow into the Gulf of Thailand. It also inhabits river basins in the Cardamom Mountains. One known collection site is the Phru To Daeng peat swamp forest in Narathiwat province. There are unconfirmed reports of its presence in Penang, Malaysia, but these are not verified.
How it lives
These fish are social and live in groups. They possess a protein encoded by the Electromagnetic Perceptive Gene, which allows them to react to electromagnetic fields. This biological trait helps them navigate and sense their environment. They are active swimmers in their native streams and rivers, relying on their transparency as a form of camouflage against predators in the clear waters of southern Thailand.
Fish and people
Aquarium enthusiasts value this fish for its ghostly appearance. Most specimens in the trade are caught from the wild, as commercial breeding is not established. This reliance on wild populations raises concerns about sustainability given their limited geographic range. In Thai culture, the fish appears in folklore. Legend says King Phra Ruang threw fish bones back into water and wished them alive, creating the glass catfish. Locals call it pla kang phra ruang, meaning Phra Ruang's skeletal fish.
Questions people ask about Glass catfish
Why is the glass catfish transparent?
The fish lacks scales and body pigment. Its skin has a plywood-like collagen structure that lets light diffract through the muscles. Most organs are near the head, leaving the rest of the body clear.
Is this fish bred in captivity?
No, it is not known to be bred at commercial facilities. The aquarium trade relies on wild-caught specimens, primarily from rivers and swamps in southern Thailand.
What is the difference between this and other glass catfish?
Until 2013, it was confused with Kryptopterus bicirrhis and K. minor. K. vitreolus is the small species common in tanks. K. bicirrhis is larger and rare in captivity, while K. minor is from Borneo.
Good reading and sources
- Kryptopterus vitreolus on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Kryptopterus vitreolus", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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