Truncata Rasbora Care Guide
Trigonostigma truncata is a harlequin rasbora described in 2020 from the east coast of the Malay Peninsula, distinguished by a truncated black body marking.
Compiled by Aquairi from published sources · Published · Updated
Overview
Trigonostigma truncata is a harlequin rasbora described by Heok Hui Tan in 2020 from the east coast of the Malay Peninsula. It resembles the well-known Trigonostigma heteromorpha but has a more truncated black body marking whose rear apex does not reach the caudal-fin base, a bluish-lilac body sheen, and a slightly larger adult size.
Taxonomy
- Family: Cyprinidae
- Genus: Trigonostigma
- Scientific name: Trigonostigma truncata
- Order: Cypriniformes
Habitat
The species is known from the east coast of the Malay Peninsula, from southern Thailand (Narathiwat) to Terengganu in Malaysia. It inhabits lowland freshwater acid swamp-forest streams that flow into riverine habitats.
Tank requirements
- Minimum tank volume: 60 L
- Temperature: 22-28 °C (72-82 °F)
- pH: 5.5-7.0
- GH: 1-8 °dGH
- School size: 8 or more individuals
- Lifespan: 4-6 years
Diet
Trigonostigma truncata is an omnivore. Based on related harlequin rasboras, a varied diet of small dried, live and frozen foods is appropriate in the aquarium.
Compatibility
This is a peaceful, middle-water schooling fish suited to soft, acidic community tanks. Compatible companions include the harlequin rasbora and small corydoras; boisterous or aggressive species should be avoided.
Truncata Rasbora (Trigonostigma truncata) Breeding Guide
Overview
Trigonostigma truncata is a harlequin rasbora described by Tan in 2020 from coastal swamp forests of the Malay Peninsula, distinguished from the common harlequin (T. heteromorpha) by its truncated black wedge marking, orange-red anal fin and shallower body. Detailed species-specific breeding accounts are scarce, so the guidance below follows the well-documented breeding pattern shared across the genus Trigonostigma.
Sexing
Within Trigonostigma, sexes are separated by the shape of the dark wedge-shaped flank marking: in males it shows a sharper, more well-defined outline, whereas in females it has a more rounded appearance. Mature females are also typically rounder-bellied.
Conditioning
For Trigonostigma, the recommended method is to feed small amounts of live and frozen foods two or three times a day in the weeks leading up to a spawning attempt, until females are full of eggs and males show their best colours.
Breeding Setup
A separate, dimly lit spawning tank containing broad-leaved plants is used so that the pair has suitable leaf undersides to deposit eggs upon, consistent with the genus pattern.
Spawning Behavior & Trigger
Across the genus, spawning is triggered by a large (40-50% of tank volume) cool water change, after which one or two pairs are introduced. Unlike scatterers, Trigonostigma pairs perform dry runs over a chosen surface and then attach eggs to the underside of a broad leaf, often spawning in an inverted position.
Egg & Fry Care
Following the genus pattern, eggs hatch in about 24 to 48 hours with fry free-swimming in around a week. First foods are Paramecium, progressing to Artemia nauplii and microworm as the fry grow.
Common Challenges
The leaf-attaching spawning mode requires healthy broad-leaved plants and soft, acidic water; because species-specific data for T. truncata is limited, the genus-typical protocol should be applied and verified against the fish's own behaviour.