Wedge-spotted rasboras (Genus Trigonostigma)

A tiny, colorful fish that can add a pop of color and dynamic movement to any freshwater aquarium is the wedge-spotted rasbora. Distinguished by their characteristic black triangle markings, these fish are a favorite among aquarians due to their calm disposition and simplicity of maintenance.

Wedge-spotted rasboras are native to Southeast Asia and grow well in warm, soft water with lots of vegetation. Especially when kept in groups, their energetic swimming and schooling behavior make them a pleasure to watch.

Wedge-spotted rasboras are a great option if you want to give your tank a bit of elegance. These resilient fish can live for several years with the right care, giving you endless pleasure as they gracefully swim through the water.

Habitat and habitat

In the reservoirs of Indonesia, the Philippines, and South and Southeast Asia, this genus is widely distributed.

The majority of the genus’ representatives are schooling fish, which reside in the upper layers of reservoirs with slowly moving water.

Description

These fish are easily recognized by their dark triangular spot and high, laterally flattened body, which gradually narrow at the back of the body and extend to the base of the caudal fin. The translation of the genus’s Latin name is "triangular spot."

Their English name, harlequin rasboras, came from this distinctive pattern.

Behavior and compatibility

Because wedge-spotted rasboras are a schooling species, they become timid when housed in an aquarium by themselves. In addition, the full beauty of their coloring, particularly in the males, is only visible when other members of their own species are nearby.

Because rasboras are so peaceful, they work well in aquariums with other peaceful fish of a similar size to create multi-species compositions.

Aquarium

The aquarium needs to hold at least 10 liters for a pair and 100 liters for a group of ten to fifteen people.

It is not difficult to prepare an aquarium for these rasboras; dark, fine-grained soil is preferred. Maintaining the background is ideal for dark tones. Various snags, bamboo branches, etc., work well as decorations. It is best to plant dense thickets of aquatic grasses in the peripheral zone. There is moderate, dispersed lighting, and floating plants serve as a light filter.

Water parameters:

In the range of 23 to 28 °C pH: between 6.0 and 7.0 St RESS: 12 ° DGH maximum

Efficient filtration and weekly water replacement of the same parameters by up to 25%.

Nutrition

Sexual dimorphism

Generally speaking, men are brighter in color and slimmer. Females that are larger have more rounded abdomens.

Breeding

Many species spawn in large groups in the natural world.

In terms of reproduction biology, representatives of this kind differ. In contrast to the other border species, the wedge-shaped gluing eggs adhere to the underside of aquatic plant leaves while they are spawning, merely scattering their caviar.

The process of breeding these fish is very intricate. Depending on the conditions of content, the fish reaches maturity in 7–10 months. They should be planted for spawning at this time. The male in a perfect pair should be one month older than the female. The producers (no more than 2 males and 3–4 females) should be divided and fed liberally, ideally with bloodworms, 10–12 days prior to spawning. The fish will also adjust to the spawning tank’s water, which has slightly different qualities than the aquarium’s.

The volume of the spawning tank should be at least 30 liters. Broad-leaved plants are required, such as Thai fern or cryptocoryne. Spawning plants should be thoroughly washed, and the aquarium should be disinfected. A net should be placed on the bottom to preserve the eggs. The water level in the spawning tank should be no more than 20 cm. The water parameters in the spawning aquarium are as follows: hardness – 4, pH 5.5 -6.5, temperature 26 – 28 ° C. Sharp changes are not allowed. Spawning water should be filtered with peat infusion until the color of green tea. Lighting is preferable scattered. However, sometimes it spawns in bright light.

The male starts to push the female down and circles above her if the conditions in the spawning tank are right. Before long, the female will start to swim above the plant leaves, occasionally even flipping over into a vertical position. The man will shortly follow her. The female lays several eggs, which stick to the leaves right away, after he wraps his body around hers. Everything is said repeatedly. Even so, some of the eggs will still drop beneath the net at the bottom of the aquarium. When spawning, the female can lay up to 300 eggs in 1.5–2 hours.

The fish should be returned to the aquarium after spawning, and the spawning tank’s walls should be made darker. After 36 hours, the larvae emerge, and by the fifth day of life, the fry can swim and feed themselves. Use brine shrimp and daphnia, which are the smallest zooplankton, as a first course. The fry require feeding multiple times a day due to their voracious appetite. They can then include special dry food in their diet. Adult fry can consume brine shrimp, cyclops, daphnia, enchytraea, corethra, and granulated feed. Rasbora fries develop rapidly.

Heteromorph or Wedge-shaped Rasbora (Trigonostigma heteromorpha)

A long-time favorite of home aquariums, the history of its maintenance goes back more than a hundred years. For most aquarists, the name rasbora is associated with this species, although, as we already know, it is the most atypical representative of this group. This is the largest up to 5 cm and high-bodied of all wedge-spotted rasboras. The body color is pinkish, a black wedge-shaped spot starting from the middle of the body, wide, evenly tapering towards the tail. In males it is clearly outlined, in females it is blurred, with a rounded lower apex. In addition, males are distinguished by a brighter red dorsal fin. The species is widespread in Thailand, Malaysia, Sumatra and Kalimantan.

Small, placid fish of the Genus Trigonostigma, wedge-spotted rasboras are a colorful addition to any community aquarium. Their unique wedge-shaped spot and shimmering scales produce a dynamic display, and they are perfect for both novice and expert aquarists due to their laid-back disposition. These fish can flourish and enhance the color and movement of your aquatic setup with the right care, which includes a well-planted tank and steady water conditions.

Rasbora Espei (Trigonostigma espei)

The previous species differs in slightly smaller sizes of elegant addition, a copper-red general color of color, more thin and more elongated with a concave lower edge with a wedge of the spot, reminiscent of a knife blade (in English this fish is called ‘Lambchop Rasbora’). Peaceful schooling fish for a community aquarium with shady areas. Dense vegetation as shelters: broad-leaved plants and soft, slightly acidic peaty water. There are two isolated populations of this species: one in the southwestern part of Thailand, the other in the southeast of the country, on the border with Cambodia. Coloration can vary significantly depending on the habitat.
Length: does not exceed 3.5 cm.
Water: temperature 23-28 C; pH slightly acidic below 7; soft, dH 2-10.
Food: live, frozen and dry.
Habitat: Thailand, Cambodia.

Hengel"s Rasbora (Trigonostigma hengeli)

Hengel’s Rasbora shares many characteristics with the previous species, making them difficult to distinguish even at a glance. This rasbora has a more faded, yellowish-gray overall color tone that makes the fiery orange spots above and in front of the dark triangle stand out. Generally speaking, it is not as large as Rasbora espei; adults are only 3.5 cm long. In Sumatra and Kalimantan, two of the Sunda Islands, the species is widely distributed.

Any aquarium would benefit from the colorful and lively addition of wedge-spotted rasboras, which add movement and color to the space. Fish enthusiasts love them because of their eye-catching appearance and characteristic wedge-shaped mark.

These fish are gregarious animals that thrive best in groups, which both supports and lessens their natural behavior. They are appropriate for both novice and seasoned aquarists because they are comparatively simple to maintain.

Wedged-spotted rasboras are a fantastic option for community tanks because of their hardiness and flexibility in different types of water. These vibrant fish will provide you years of enjoyment if you give them a well-planted habitat and keep the water’s parameters consistent.

Video on the topic

Wedge-spotted rasbora (Trigonostigma heteromorpha)

This fish will decorate any aquarium – Wedge-spotted rasbora (Trigonostigma heteromorpha)

WEDGE-SPONTANEOUS RASBORA. BREEDING.(English subtitles)

Wedge-spotted rasbora – a popular small fish