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No federal permit to keepKryptopterus geminus
Kryptopterus geminus
Fishes › Catfish (Siluriformes) › Siluridae (Glass and sheat catfish)
Kryptopterus geminus is a species of catfish belonging to the family Siluridae.
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 6.7 in / 17.06 cm).
- Water: Freshwater (tolerates brackish).
- Layout: Lives on or near the bottom: floor space and hiding places matter more than height.
- Diet: A predator: feed meaty foods sized to its mouth (frozen fish, shrimp, worms); it will eat tankmates that fit in its mouth. FishBase classes it as a carnivore.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 59 × 18 in (roughly 80 US gallons); space needed is rated “very large tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 68–82 °F, pH 6–7.5, 2–15 dGH.
- Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Décor is relatively unimportant although this species prefers weakly-lit conditions and may become skittish in the absence of cover.”
- Diet: “Probably a predator feeding on crustaceans, invertebrates and smaller fishes in nature, although there should be no need to use such live foods in captivity.”
- Tankmates: “Generally peaceful though it may predate on smaller fishes and is somewhat timid so does not compete well with much larger, robust or otherwise boisterous species.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Glass and sheat catfish
Applies to most species in this group. Habitat: The listed Asian silurids inhabit rivers, canals and seasonal floodwaters, while Kryptopterus macrocephalus specializes in peat-swamp forest and associated blackwater streams. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- For Kryptopterus bicirrhis, provide at least a 120 × 45 cm (about 48 × 18 inch) tank footprint, subdued light and cover.
- For K. macrocephalus, provide at least a 120 × 30 cm (about 48 × 12 inch) footprint, floating vegetation and a well-decorated dim environment.
- For Ompok bimaculatus, provide at least 180 × 60 × 60 cm (about 72 × 24 × 24 inches), open swimming room and suitably sized pipe shelters.
- Use mature filtration and regular water changes; Ompok needs powerful filtration to handle its waste and benefits from some current.
- Match chemistry to identity: K. macrocephalus is maintained at pH 4.0–7.0 and 1–8 dGH; Ompok has a much broader reported pH 6.0–8.0 and 4–28 dGH tolerance.
Climate & lighting
| Water | 68–78.8°F |
Diet
- Sinking prepared carnivore foods for established Kryptopterus.
- Bloodworm and other appropriately sized frozen invertebrates.
- Small earthworms for Kryptopterus; larger worms for Ompok.
- Prawn and mussel pieces for larger Ompok.
Social life
- Keep K. bicirrhis and K. macrocephalus in conspecific groups of at least four. Avoid boisterous competitors and fish small enough to swallow; Ompok is a much larger predator despite its relatively shy disposition.
Health watch
- Ammonia injury from failed filtration.
- Bacterial skin or fin infections associated with poor water quality.
Understanding the animal
About this animal
About this animal
It can be distinguished from all its congeners, with the exception of Kryptopterus cryptopterus, by the almost flat dorsal profile with no concavity behind the head. This species grows to a length of 17.1 centimetres (6.7 in) SL. Examples of this distinctively shaped, translucent fish used to be assigned to the long-established species K. cryptopterus but recent studies have shown several small but consistent differences which prompted the erection of this new species.
Quoted from the Wikipedia article “Kryptopterus geminus” (CC BY-SA 4.0) 174
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater and brackish water, in rivers and streams. Stays near the bottom. Occurs in large rivers with turbid waters. |
| Water it lives in | Freshwater / brackish water. |
| Climate | Tropical climate. |
| Wild diet | Hunting macrofauna (predator). |
What this means for care
- It tolerates or needs brackish water; check salinity needs before setup.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 95°F (up to 98°F in the hottest sampled areas) |
| Cool-season lows | about 66°F (down to 59°F in the coldest sampled areas) |
| Average temperature | 79–82°F across sampled records |
| Relative humidity | 71–74% on average (driest month about 61%) |
| Rainfall | about 1352 mm a year, with strong wet and dry seasons |
Measured at 37 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | Kryptopterus geminus is a species of catfish belonging to the family Siluridae. It can be distinguished from all its congeners, with the exception of Kryptopterus cryptopterus, by the almost flat dorsal profile with no concavity behind the head. This species grows to a length of 17.1 cm SL. Examples of this distinctively shaped, translucent fish used to be assigned to the long-established species K. cryptopterus but recent studies have shown several small but consistent differences which prompted the erection of this new species. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| Biology | Occurs in large rivers with turbid waters and in streams and canals. Feeds on fish, prawns, insects and their larvae. Spawns during the early part of the rainy season. — FishBase |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 59 × 18 in (about 80 US gallons).
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Seriously Fish: Kryptopterus bicirrhis Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Kryptopterus macrocephalus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Ompok bimaculatus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- FishBase: Kryptopterus geminus Peer-reviewed researchAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
