Photo: No machine-readable author provided. Daiju Azuma assumed (based on copyright claims). (CC BY-SA 2.5) — via Wikimedia Commons
Glass Catfish (Kryptopterus vitreolus)
The living X-ray: a fully transparent, schooling catfish that reveals every bone and organ — and vanishes from stress if kept alone.
Will it live with a Glass Catfish?
We compare each fish against your glass catfish on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Ash Lipped Apisto✅ CompatibleSemi-aggressive · 7 cm · Hard care · 24–29 °C (75–84 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Banded Dwarf Cichlid✅ CompatibleSemi-aggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Black Kuhli Loach✅ CompatiblePeaceful · 8 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Bleeding Heart Tetra✅ CompatibleSemi-aggressive · 7 cm · Medium care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Bleeding Heart Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bolivian Ram✅ CompatiblePeaceful · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Bright Diamond Tetra✅ CompatiblePeaceful · 7 cm · Hard care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
- Brilliant Rasbora✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Brilliant Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Buenos Aires Tetra✅ CompatibleSemi-aggressive · 7 cm · Easy care · 18–26 °C (64–79 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Burmese Loach✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Celebes Rainbowfish✅ CompatiblePeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Celebes Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Clown Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Costa's Tetra✅ CompatiblePeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
- Croaking Gourami✅ CompatiblePeaceful · 7 cm · Easy care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Gold Barb✅ CompatiblePeaceful · 7.5 cm · Easy care · 18–26 °C (64–79 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Gold Barb in a shoal of 6+ or it gets stressed and nippy.
- Hongsloi Dwarf Cichlid✅ CompatibleSemi-aggressive · 7 cm · Medium care · 24–29 °C (75–84 °F)
- Peaceful + Semi-aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Leopard Frog Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 25–30 °C (77–86 °F)
- Both are peaceful, and their water overlaps around 25–28 °C — no size, zone or temperament conflicts.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Mahachai Betta✅ CompatibleAggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
- Peaceful + Aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Melon Barb✅ CompatiblePeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Melon Barb in a shoal of 8+ or it gets stressed and nippy.
- Peacock Gudgeon✅ CompatiblePeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Peppered Corydoras✅ CompatiblePeaceful · 7 cm · Easy care · 18–26 °C (64–79 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Peppered Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Rounded Filament Barb✅ CompatiblePeaceful · 7 cm · Medium care · 22–27 °C (72–81 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Rounded Filament Barb in a shoal of 6+ or it gets stressed and nippy.
- Roundtail Paradise Fish✅ CompatibleSemi-aggressive · 7 cm · Easy care · 10–26 °C (50–79 °F)
- Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Splashing Tetra✅ CompatiblePeaceful · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Splashing Tetra in a shoal of 6+ or it gets stressed and nippy.
- Thick-lipped Gourami✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- African Butterfly Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 22–28 °C (72–82 °F)
- African Butterfly Cichlid and Glass Catfish are close in size, but the semi-aggressive one tends to dominate — add glass catfish in a group to spread the pressure.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Agassiz's Dwarf Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 24–30 °C (75–86 °F)
- Agassiz's Dwarf Cichlid and Glass Catfish are close in size, but the semi-aggressive one tends to dominate — add glass catfish in a group to spread the pressure.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Amazon Puffer⚠️ With cautionPeaceful · 8 cm · Medium care · 23–28 °C (73–82 °F)
- Your 80 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Badis⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Badis and Glass Catfish are close in size, but the semi-aggressive one tends to dominate — add glass catfish in a group to spread the pressure.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Bamboo Shrimp⚠️ With cautionPeaceful · 8 cm · Medium care · 22–27 °C (72–81 °F)
- Glass Catfish may eat Bamboo Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Bandit Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 22–26 °C (72–79 °F)
- Bandit Cichlid is semi-aggressive and may chase or nip the smaller Glass Catfish — plant heavily and break up sight lines.
- Your 80 L tank is below the ~150 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Bandit Cichlid in a shoal of 6+ or it gets stressed and nippy.
- Brichardi Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 24–28 °C (75–82 °F)
- Different pH ranges (6–7.5 vs 7.8–9); doable if you sit in the shared band, but not ideal long-term.
- Expect Brichardi Cichlid to harass Glass Catfish at times; give dense cover and watch them at feeding.
- Your 80 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Cockatoo Dwarf Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Cockatoo Dwarf Cichlid is semi-aggressive and may chase or nip the smaller Glass Catfish — plant heavily and break up sight lines.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Congo Tetra⚠️ With cautionPeaceful · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Your 80 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Demasoni Cichlid⚠️ With cautionAggressive · 9 cm · Hard care · 23–27 °C (73–81 °F)
- Different pH ranges (6–7.5 vs 7.8–8.6); doable if you sit in the shared band, but not ideal long-term.
- Demasoni Cichlid and Glass Catfish are close in size, but the aggressive one tends to dominate — add glass catfish in a group to spread the pressure.
- Your 80 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Demasoni Cichlid in a shoal of 12+ or it gets stressed and nippy.
- Dwarf Gourami⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Dwarf Gourami is semi-aggressive and may chase or nip the smaller Glass Catfish — plant heavily and break up sight lines.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Goldeneye Dwarf Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Easy care · 24–28 °C (75–82 °F)
- Goldeneye Dwarf Cichlid and Glass Catfish are close in size, but the semi-aggressive one tends to dominate — add glass catfish in a group to spread the pressure.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Lifalili Jewel Cichlid⚠️ With cautionAggressive · 9 cm · Medium care · 22–28 °C (72–82 °F)
- Expect Lifalili Jewel Cichlid to harass Glass Catfish at times; give dense cover and watch them at feeding.
- Your 80 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Mexican Tetra⚠️ With cautionSemi-aggressive · 9 cm · Easy care · 18–25 °C (64–77 °F)
- Mexican Tetra is semi-aggressive and may chase or nip the smaller Glass Catfish — plant heavily and break up sight lines.
- Your 80 L tank is below the ~110 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Mexican Tetra in a shoal of 6+ or it gets stressed and nippy.
- Pantanal Corydoras⚠️ With cautionPeaceful · 8 cm · Medium care · 22–27 °C (72–81 °F)
- Your 80 L tank is below the ~110 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Pantanal Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Scissortail Rasbora⚠️ With cautionPeaceful · 8 cm · Easy care · 22–27 °C (72–81 °F)
- Your 80 L tank is below the ~90 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Scissortail Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Cherry Shrimp⛔ Not recommendedPeaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
- Glass Catfish will hunt and eat Cherry Shrimp — keep shrimp only with small, peaceful, non-predatory fish.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Cherry Shrimp in a shoal of 10+ or it gets stressed and nippy.
- Crystal Red Shrimp⛔ Not recommendedPeaceful · 2.5 cm · Hard care · 20–24 °C (68–75 °F)
- Glass Catfish will hunt and eat Crystal Red Shrimp — keep shrimp only with small, peaceful, non-predatory fish.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Crystal Red Shrimp in a shoal of 10+ or it gets stressed and nippy.
- Goldfish⛔ Not recommendedPeaceful · 30 cm · Medium care · 18–22 °C (64–72 °F)
- Temperature needs don't overlap (Glass Catfish 23–28 °C vs Goldfish 18–22 °C).
- Goldfish may bully the smaller Glass Catfish, though its armour makes it a hard meal — give it caves and driftwood to retreat into.
- Your 80 L tank is below the ~150 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Imperial Flower Loach⛔ Not recommendedSemi-aggressive · 50 cm · Hard care · 15–22 °C (59–72 °F)
- Temperature needs don't overlap (Glass Catfish 23–28 °C vs Imperial Flower Loach 15–22 °C).
- Expect Imperial Flower Loach to harass Glass Catfish at times; give dense cover and watch them at feeding.
- Imperial Flower Loach may bully the smaller Glass Catfish, though its armour makes it a hard meal — give it caves and driftwood to retreat into.
- Your 80 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Tiger Shrimp⛔ Not recommendedPeaceful · 3 cm · Hard care · 20–25 °C (68–77 °F)
- Glass Catfish will hunt and eat Tiger Shrimp — keep shrimp only with small, peaceful, non-predatory fish.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Keep Tiger Shrimp in a shoal of 6+ or it gets stressed and nippy.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Glass Catfish care specs
- Care level
- Medium
- Breeding
- Very Hard
- Max size
- 8 cm (3.1 in)
- Min tank size
- 80 L (21.1 gal)
- Temperature
- 23–28 °C (73–82 °F)
- pH
- 6–7.5
- Hardness
- 5–12 dGH
- Lifespan
- 3–8 years
- Diet
- Carnivore
- Swim level
- Middle
- Group size
- 6+ (shoaling)
- Family
- Siluridae
- Origin
- Southeast Asia — Thailand, Malay Peninsula (Mekong and Chao Phraya river basins)
What is a Glass Catfish?
The Glass Catfish (Kryptopterus vitreolus) is one of freshwater fishkeeping’s most visually arresting species — a schooling catfish whose body is almost entirely transparent, leaving its spine and internal organs on full display. In good light the fish glows with a faint iridescent shimmer; under a torch, you can count vertebrae. That spectacle is not a gimmick. It reflects a genuinely unusual adaptation to life in clear, moderately swift tropical rivers, where near-invisibility is a survival tool.
Despite the common name, K. vitreolus is not the same fish as the older trade name Kryptopterus bicirrhis — a larger, more difficult species that was sold as “glass catfish” for decades. The fish now routinely available in the hobby, and the one this profile covers, tops out at around 8 cm (3.1 in) and is more tractable in a well-managed community setup. It belongs to the family Siluridae, the true catfishes, and like its relatives it lacks scales and carries a pair of long maxillary barbels that sweep forward as it hovers.
Where do Glass Catfish come from?
Wild Glass Catfish inhabit the Mekong and Chao Phraya river basins of Thailand and the Malay Peninsula — clear, relatively fast-flowing streams and river margins with moderate current, sandy or silty substrates, and plenty of submerged vegetation along the banks. The water there is soft to moderately hard, slightly acidic to neutral, and well-oxygenated. Seasonal flooding expands and contracts their range, but they are not floodplain generalists — they prefer clear, cooler stretches over turbid, warm, still backwaters.
That origin shapes every aspect of good care: these fish want water movement, moderate temperatures, soft-to-neutral chemistry, and cover in the form of plants or driftwood. A stagnant, warm, bare tank is exactly what they did not evolve for.
What size tank does a Glass Catfish need?
The 80-litre (21 US gal) minimum in the quick-facts is the true floor for a small group, and it is tight. A 120–150 L (32–40 gal) tank gives a shoal of six to eight fish far more comfortable mid-water space and makes water quality easier to maintain. Tank footprint matters more than height — Glass Catfish are active horizontal swimmers, not climbers.
Length is the other consideration: the tank should be long enough that the school can swim together in formation without constantly turning. A 90 cm (36 in) or longer tank is ideal. Avoid tall, narrow tanks; the mid-water zone is their home and they rarely venture to the surface or the bottom.
A secure lid is good practice — though not the escape artists bettas are, any fish can jump when startled.
What water parameters do Glass Catfish need?
- Temperature: 23–28 °C (73–82 °F). The cooler end of this range is fine and actually preferred by many keepers; sustained temperatures above 28 °C stress them.
- pH: 6.0–7.5. They are forgiving across this range; wild populations live in slightly acidic water, but captive-bred fish adapt to neutral chemistry without issue.
- Hardness: 5–12 dGH — soft to moderately hard. Very hard water is to be avoided.
Parameter stability matters more than hitting exact targets. Glass Catfish react badly to sudden swings — a well-cycled, established tank with consistent weekly water changes (around 25–30%) keeps them healthy far better than a tank where numbers look right on paper but fluctuate daily. Adding tannins via driftwood or Indian almond leaves softens the water gently and darkens it in a way that reduces fish stress and mimics their natural habitat. Gentle flow from a spray bar or a diffused output is preferable to a powerhead blasting the midwater zone.
What do Glass Catfish eat?
Glass Catfish are carnivores with a preference for small, live or frozen invertebrates. In the wild they intercept drifting zooplankton and small aquatic insects in the current. In captivity the best staples are:
- Frozen bloodworm — accepted readily, high in protein; use as a regular component rather than an exclusive treat.
- Frozen or live daphnia — ideal; small particle size suits their mouth and the water flea’s movement triggers a strong feeding response.
- Baby brine shrimp (BBS) — excellent for newly acquired or shy fish.
- Micro-worms and white worms — useful variety.
- Quality micro-pellets or small floating pellets — accepted by settled fish; choose a reputable brand with a high animal-protein content.
Feed small amounts twice daily. Because Glass Catfish hover in mid-water, food needs to reach that zone — slow-sinking or suspended particles work better than pellets that sink straight to the substrate before the fish react. Rinse frozen foods before feeding and remove any uneaten food after a few minutes; uneaten protein rots quickly in a planted setup.
Are Glass Catfish aggressive — and what fish can live with them?
Glass Catfish are thoroughly peaceful and pose no threat to any fish they cannot fit in their mouths. The compatibility concern runs in the opposite direction: their transparent, delicate bodies and calm mid-water hovering make them easy targets for nippy or aggressive tank mates, and fin-nippers will strip their barbels and fins with visible speed.
Good tank mates share their preference for gentle flow and similar water chemistry. Proven companions include:
- Small tetras — ember, harlequin rasbora, chili rasbora, neon and cardinal tetra
- Corydoras — active at the bottom while Glass Catfish own the middle
- Smaller rasboras and danios (not overly boisterous)
- Dwarf gouramis (with caution — watch for aggression from the gourami)
- Small peaceful loaches like kuhli loaches
Avoid: cichlids of any real size, goldfish (different temperature requirements), tiger barbs, serpae tetras, or any fish known to nip fins.
For a full compatibility breakdown, see Glass Catfish tank mates.
How do you tell male and female Glass Catfish apart?
Sexing Glass Catfish is genuinely difficult — the species shows minimal external sexual dimorphism. The most reliable indicator is body depth: females may appear slightly deeper-bodied when gravid, as eggs can sometimes be faintly visible through the transparent body wall in a well-fed, conditioned female. Outside of that gravid window, males and females look essentially identical in coloration, fin shape and body proportions.
In practice, a group of six or more bought together from the same stock will almost certainly include both sexes. There is no reliable way to sex juveniles. If conditioning for breeding, buy a larger group (eight to ten) to improve the probability of getting a mixed-sex cohort.
How do Glass Catfish breed?
Breeding Glass Catfish in captivity is rated Very Hard and has only been achieved by a small number of dedicated hobbyists. They do not breed readily in standard aquarium conditions, and there is no established, repeatable protocol with wide documentation.
What is known from the rare successful accounts: conditioning the group with varied live foods over several weeks appears important, as does simulating a seasonal trigger — often a gradual drop in temperature by a few degrees followed by a slow return to the upper range, combined with slightly more acidic water and a reduced photoperiod, mimicking the onset of their breeding season in the wild. Eggs, when produced, are small and scattered among fine-leaved plants.
Raising fry requires very fine live foods (infusoria, rotifers) and exceptional water quality. This is a species where breeding success is a genuine achievement rather than a routine outcome.
What are common Glass Catfish diseases?
Glass Catfish are not unusually disease-prone, but their lack of scales makes them more susceptible to skin-irritating pathogens and more sensitive to salt or harsh treatments than scaled fish. Common issues to watch for:
- Ich (white spot disease) — white pinhead dots on the body or fins. Usually introduced through new fish or plants; prevented by quarantining new arrivals for four to six weeks.
- Skin flukes and external parasites — loss of transparency, flashing (rubbing against surfaces), and abnormal behaviour can all signal parasitic irritation.
- Bacterial infections and fin deterioration — almost always tied to poor water quality or injury from nipping tank mates; the best prevention is stable, clean water and compatible companions.
- Stress-related loss of transparency — not a disease but a reliable early-warning sign; see the FAQ above.
Prevention follows the same principles as any community fish: a mature, cycled tank, stable parameters, a varied diet, and quarantine for all new arrivals before they join the display tank.
Health note: confirming a diagnosis before treating is especially important for Glass Catfish — their scaleless bodies mean some standard-dose medications can cause harm. Always verify symptoms against a reputable veterinary or specialist aquatic-health source before medicating, and dose cautiously.
How long do Glass Catfish live?
A well-kept Glass Catfish can live 3 to 8 years, with 4–6 years being a realistic expectation under good aquarium conditions. The wide range reflects both individual variation and the strong influence of husbandry: fish kept in stable, planted setups with appropriate group sizes and a varied diet consistently outlive those kept in marginal conditions.
Because they are shoaling fish, the health of the group affects individual longevity. A single fish kept alone rarely reaches the upper end of that range — chronic stress shortens life substantially. Keep a minimum of six, maintain water quality diligently, and these extraordinary little fish will reward you with years of mid-water spectacle.
Frequently asked questions
Why does my glass catfish look white or cloudy instead of transparent?
Loss of transparency is a stress alarm: it usually means the group is too small, the tank is too bright, flow is too strong, or water parameters have slipped. Start with group size — fewer than six individuals almost always triggers chronic stress. Add denser planting and check that temperature and pH are within range. Once conditions improve the glass-like clarity typically returns within days.
What do glass catfish eat, and how do I get them feeding?
Glass catfish are mid-water carnivores that prefer live or frozen foods — daphnia, baby brine shrimp, bloodworm and micro-worms are all excellent. High-quality small sinking or floating micro-pellets are accepted once fish are settled, but shy new arrivals often need live food to trigger the initial feeding response. Feed small amounts twice daily; uneaten food degrades water quality quickly in a planted setup.
What you need to keep a glass catfish
The baseline is a heated, filtered 80 L+ tank: a reliable heater to hold 23–28 °C (73–82 °F), a gentle filter that won't batter a glass catfish in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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