Sheatfishes (Siluridae)

Glass Catfish

Kryptopterus vitreolus

Kryptopterus vitreolus, known as the glass catfish, belongs to the family Siluridae. It stands out among catfishes for its remarkably transparent body, through which the fish's skeleton can be observed. This unusual evolutionary adaptation, combined with its ease of care and peaceful nature, has earned this species widespread popularity among aquarium enthusiasts worldwide.

Tank
from 81 L (21 gal), 100 L (26 gal) recommended
Temperature
20 – 26 °C (68 – 79 °F)
Size in aquarium
5 – 6.5 cm (2 – 2.6 in)
Acidity
pH 4–7
Natural rangeRange on the map
  • Gulf of Thailand drainage area
  • Thailand

Tank conditions

Plan the tank stocking
Temperature
20 – 26 °C (68 – 79 °F)
Water pH
Acidic (4) – Neutral (7)
Water dH
Very soft (1) – Medium hardness (10)
Water salinity
no salt (freshwater)
Size in aquarium
5 – 6.5 cm (2 – 2.6 in)
Lifespan
7 years
Temperament
Peaceful (regular)
Toward small fish
not a predator
Required aquarium volume
from 81 L (21 gal), 100 L (26 gal) recommended
Lighting
dimmed
Substrate
any (no restrictions)
Water flow
weak or moderate
Feeding
Any (universal)
Keeping
Medium group 6–8 individuals
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. The 81 L minimum corresponds to a tank footprint of 90×30 см. The recommended 100 L is for the group size given under keeping mode.

Care and keeping

Description

The glass catfish has an elongated and tall body, with an unusually long anal fin that extends from the head to the very tail. Its main distinguishing feature is its transparent body, through which the spine and ribs are clearly visible. Near the mouth on its head are two sensitive, long, antenna-like barbels.

Habitat

Its natural habitat is in the river systems of Southeast Asia, primarily in modern-day Thailand. Specifically, these fish are found in rivers that flow into the Gulf of Thailand. Due to potential confusion within the species, a precise definition of its habitat range requires further research. The catfish prefers to live in still or slow-moving waters, which are often quite murky.

Behavior and Compatibility

These catfish thrive best in a shoal of at least 6 individuals. Their behavior is calm and peaceful, one might even say modest. It is advisable to avoid cohabitation with active or aggressive species, as well as those significantly larger than them. Other peaceful and small fish typical of Southeast Asia get along wonderfully with glass catfish.

Care and Maintenance

A group of several fish will feel comfortable in an aquarium of 100 liters or more. The decor should include many rooted and floating plants; the latter create additional shading, which is beneficial for these fish. The choice of substrate depends on the needs of the plants and is not critical for the catfish, as they prefer to stay in the middle or upper water layers. Water parameters should be as close as possible to their natural habitat, meaning the water should be soft (in terms of dGH) and slightly acidic (pH). Adding a few dry fallen leaves can give the water a characteristic “tea” tint due to the release of tannins, mimicking the conditions of slow-flowing swamps or marshy river sections in the tropics. More detailed information on dH and pH parameters can be found in the “Hydrochemical Composition of Water” section. The minimum equipment set includes a heater, an aerator, a filter (preferably one that does not create a strong current), and a lighting system set for subdued light. Aquarium care for glass catfish includes daily feeding, regular cleaning of the substrate from organic waste (food remnants, excrement), and weekly water changes of 15–20%. The frequency of changes depends on the number of inhabitants and the efficiency of the filtration system.

Diet

In their natural habitat, the glass catfish acts as a small predator, whose diet consists of zooplankton and various invertebrates. If kept in a home aquarium, the fish will happily consume all types of dry foods, be it flakes or pellets. These should be supplemented with live or frozen meaty foods, such as bloodworms, daphnia, grindal worms, and brine shrimp. It is important to ensure a varied diet! Feeding is recommended 2–3 times a day, offering an amount of food that the fish can consume within 5 minutes.

Breeding and Reproduction

No cases of successful breeding of glass catfish in home aquarium conditions have been recorded; at least, the author has not found such information. These fish are supplied to retail and wholesale networks by breeders from Asia, where they are bred on specialized fish farms organized directly in their natural environment.

Diseases

Catfish are very sensitive to water quality and composition; any changes in parameters or deterioration of conditions immediately affect their well-being. This increases the fish's susceptibility to infections and can lead to various diseases. In a biologically balanced aquarium with suitable conditions, health problems usually do not arise.

How to choose

When purchasing, choose only active individuals that stay in a shoal and show no signs of emaciation. Avoid fish with cloudy eyes, damaged fins, or visible spots on their transparent bodies, as glass catfish are extremely sensitive to transport conditions and stress. At the store, be sure to ask how long the fish have been imported and prefer individuals that have already undergone an adaptation period in the aquarium. Given that the species is often sourced from the wild, it is important to ensure the absence of parasites and signs of bacterial infections that may appear in the first few days after relocation. Remember that quarantine for new individuals is a mandatory condition before introducing them to the main aquarium.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Glass Catfish get?

An adult reaches 5–6.5 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Glass Catfish need?

The recommended volume is 100 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Glass Catfish need?

Temperature 20–26 °C, pH 4–7, hardness 1–10 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Glass Catfish live?

Around 7 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Glass Catfish aggressive?

Temperament: peaceful (regular). Keep this in mind when choosing tank mates.

How many Glass Catfish should be kept together?

Recommended setup: medium group (6–8 individuals). Ignoring this is a common cause of stress and disease.

What does Glass Catfish eat?

Diet type: any (universal). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Glass Catfish?

The scientific name of the species is Kryptopterus vitreolus, family Sheatfishes (Siluridae).

Similar fishes

Matched by family, categories and overlapping keeping conditions

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Other scientific names and conservation status

Categories
Catfish
Conservation status
Least concernLC