Home / Fishes / Carp, barbs, minnows, loaches / Danionidae / Trigonopoma gracile
No federal permit to keepTrigonopoma gracile
Trigonopoma gracile
Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Danionidae (Danios and rasboras)
Trigonopoma gracile is a species of freshwater ray-finned fish belonging to the family Danionidae.
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 2.2 in / 5.5 cm).
- Water: Freshwater.
- Temperature: 72–75°F (range recorded for this species).
- pH: 6.5–7.
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
- Availability: Rarely or never seen in the aquarium trade; expect to source it from specialists or not at all.
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 30 × 12 in (roughly 18 US gallons); space needed is rated “modest tank”.
- Water: soft, acidic water, 70–79 °F, pH 4–7, 0–10 dGH.
- Behaviour: a shoaling fish best kept in a group of six or more; suited to a community tank.
- Difficulty: Easy (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Choice of décor is not especially critical though it tends to show better colouration in a heavily-planted set-up with a dark substrate.”
- Diet: “Likely to be a micropredator feeding on small insects, worms, crustaceans, and other zooplankton in nature.”
- Tankmates: “An ideal addition to a peaceful community of Southeast Asian fishes with comparably-sized cyprinids, small loaches, and certain anabantoids perhaps constituting the best choices.”
- Breeding: “Possibly unrecorded but recommendations for related species are as follows: Like most small cyprinids Trigonopoma spp.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Danios and rasboras
Applies to most species in this group. Habitat: These Asian fishes occupy habitats ranging from zebra-danio pools and rice paddies to shaded harlequin streams, rocky Devario streams and planted galaxy-rasbora wetlands. [fg159-zebra, fg159-harlequin, fg159-giant, fg159-galaxy]. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- Use at least 90 × 30 cm (36 × 12 in) for zebra danios.
- Harlequins require at least 60 × 30 cm (24 × 12 in), shaded planted cover and subdued light.
- Devario aequipinnatus needs at least 120 × 45 cm (48 × 18 in), oxygenated water, moderate flow and a tight lid.
- Galaxy rasboras need dense planting and broken sight lines in at least 45 × 30 cm (18 × 12 in), with gentle sponge filtration.
- Match chemistry: harlequins pH 5.0–7.5, 1–12 dGH; galaxy rasboras pH 6.5–7.5, 5–15 dGH.
Climate & lighting
| Water | 64.4–77°F |
Diet
- Quality flakes or granules sized to the fish.
- Live or frozen Daphnia and Artemia.
- Bloodworms for zebra danios, harlequins and Devario.
- Small sinking foods for galaxy rasboras, which rarely feed at the surface.
Social life
- Keep zebra danios and harlequins in groups of at least 8–10. Galaxy males spar: dense cover and larger groups distribute aggression. Active Devario can overwhelm timid feeders.
Health watch
- Pseudoloma microsporidiosis in zebra danios.
- Pleistophora infection and columnaris can produce similar white lesions in zebra danios.
- Nipped fins among rival galaxy males.
Understanding the animal
About this animal
About this animal
This species is found in Indonesia and Malaysia. A common name in use is Graceful Rasbora.
Quoted from the Wikipedia article “Trigonopoma gracile” (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. Uses both the bottom and open water. Common in forest streams and clear black water. |
| Water it lives in | Freshwater, 72–75 °F (22–24 °C), pH 6.5–7, hardness 10 dH. |
| Climate | Tropical climate. |
What this means for care
- Keep water within its wild range, 72–75 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 89°F (up to 90°F in the hottest sampled areas) |
| Cool-season lows | about 72°F (down to 71°F in the coldest sampled areas) |
| Average temperature | 79–81°F across sampled records |
| Relative humidity | 81–84% on average (driest month about 79%) |
| Rainfall | about 2698 mm a year, spread fairly evenly |
Measured at 53 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 | Trigonopoma gracile is a species of freshwater ray-finned fish belonging to the family Danionidae. This species is found in Indonesia and Malaysia. A common name in use is Graceful Rasbora. — 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 |
| Appearance and size | Differs from all of its congeners by the following combination of characters: lateral line incomplete to absent, perforating 0–6 scales; 29–32 scales along normal course of lateral line; a conspicuous black (bluish black in life) lateral stripe from tip of snout to extremity of median caudal rays; body slender, its depth 4.4-4.8 times in SL (4.0-5.1); caudal peduncle slender than all other Rasbora, its depth 2.3-2.8 times in its length (2.3-3.3); and long and pointed dorsal and anal fins. — Wikipedia (community-edited) |
| Biology | Common in forest streams and clear black water. Maximum length 15 cm TL in. — 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 in nature; aim for the middle.
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 30 × 12 in (about 18 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: Zebra danio (Danio / Brachydanio rerio) Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Trigonostigma heteromorpha Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Devario aequipinnatus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Danio / Celestichthys margaritatus Experienced keeper or breederAdded 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.
- iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.
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