Halfbeak - Dermogenys pusilla
Scientific name: Dermogenys pusilla
Common name: Halfbeak
Family: Zenarchopteridae
Usual size in fish tanks: 6 - 7 cm (2.36 - 2.76 inch)
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Recommended pH range for the species: 7 - 8
Recommended water hardness (dGH): 12 - 18°N (214.29 - 321.43ppm)
0°C 32°F30°C 86°F
Recommended temperature: 20 - 28 °C (68 - 82.4°F)
The way how these fish reproduce: Pseudo-Livebearer
Where the species comes from: South Asia
Temperament to its own species: peaceful to females
Temperament toward other fish species: peaceful
Usual place in the tank: Top levels
Food and Feeding
Halfbeak fish are carnivorous and have a strong preference for live or frozen foods. In the wild, they feed on small insects, mosquito larvae, worms, and tiny crustaceans. In captivity, it's important to mimic their natural diet by offering a variety of high-protein foods. Ideal options include:
- Mosquito larvae
- Bloodworms
- Daphnia
- Brine shrimp
- Insects (small flies or ants)
Supplement their diet occasionally with high-quality flakes or pellets designed for carnivorous fish. Feed them small portions two to three times a day to prevent overfeeding and to keep the water clean.
Sexing
Halfbeaks are sexually dimorphic, meaning males and females differ noticeably in appearance. Males are typically smaller, more colorful, and have a specialized reproductive organ called a gonopodium, which is a modified anal fin used for inseminating females. Females, on the other hand, are generally larger, less colorful, and lack the gonopodium. This sexual dimorphism makes it relatively easy to distinguish between the sexes in a tank setting.
Breeding and Reproduction
Halfbeaks exhibit a range of interesting reproductive strategies. They are considered pseudo-livebearers, meaning that they give birth to live young after a period of internal incubation. There are three known methods of reproduction in Halfbeaks:
- Some females lay fertilized eggs that hatch after a short incubation period.
- Others incubate the eggs inside their bodies and release the eggs just before hatching.
- In some cases, females give birth to fully developed live fry, which have been nourished internally by the mother.
Halfbeaks tend to have small broods of large, well-developed fry, which can remain under the mother’s protection for up to three months. It's important to provide hiding spots for the fry in the aquarium to protect them from potential predators, even from other fish in the tank.
Origin and Natural Habitat
The Halfbeak fish is widely distributed in Southeast Asia. They are native to a variety of environments ranging from freshwater to brackish and coastal waters. Some species are even found in slightly salty environments, which makes them highly adaptable to different water conditions. Dermogenys pusilla can be found in regions like Singapore, Thailand, Indonesia, Malaysia, and parts of New Zealand. In the wild, these fish typically inhabit slow-moving rivers, streams, and coastal areas where the water is calm and filled with dense vegetation.
Tank Requirements and Setup
To keep Halfbeaks healthy and thriving, it’s important to recreate their natural environment in the tank:
- Tank Size: A minimum of 40 liters (10 gallons) is recommended for a small group of Halfbeaks.
- Water Parameters: Maintain a pH between 7.0 and 8.0, with water hardness (dGH) between 12 and 18°N (214.29 - 321.43 ppm). The ideal temperature range is between 20 - 28°C (68 - 82.4°F).
- Substrate and Decorations: Use soft sand or fine gravel as a substrate. Add plenty of floating plants to give the fish shelter and reduce stress. Driftwood and smooth rocks can also be added to create a natural-looking environment.
- Filtration and Water Flow: Use a gentle filter that provides good water circulation without creating strong currents, as Halfbeaks prefer calm water.
Since Halfbeaks spend most of their time near the surface, ensure the tank has a secure lid to prevent them from jumping out.
Temperament and Tank Mates
Halfbeaks are generally peaceful fish that do well in community tanks. Males may sometimes exhibit mild aggression toward each other, especially in smaller tanks, but this behavior can be minimized by keeping them in larger groups and providing plenty of hiding spaces. They are peaceful toward other species, making them compatible with other small, non-aggressive fish like:
- Small tetras
- Rasboras
- Peaceful livebearers
- Small gouramis
Avoid keeping Halfbeaks with larger or aggressive fish that may see them as prey.
Short Description
The Halfbeak fish is a unique species known for its elongated lower jaw, peaceful temperament, and ability to live in freshwater, brackish, and slightly salty environments. With their interesting reproductive strategies and peaceful nature, Halfbeaks make an intriguing addition to any community tank. They are particularly well-suited to experienced aquarists who can provide the appropriate water conditions and diet.
Picture
Bought by aqua-fish.net from jjphoto.dk.