Wrestling halfbeak
Dermogenys pusilla
Also known as Dermogenys pusillus
FreshwaterBrackishFish
Care at a glance
- Temperature
- 75–82°F
- 24–28°C
- pH
- 6.5–7.5
- Adult size
- 2.8 in
- 7 cm
- Minimum tank
- 25 gal
- 95 L
- Temperament
- Mostly peaceful
- Social behavior
- Social
- Swim level
- Top
- Difficulty
- Medium
- Breeding
- Hard
- Rarity
- Rare
- Family
- Zenarchopteridae
- Origin
- Southeast Asia
Overview
The wrestling halfbeak is a slender surface fish that should be kept in a group, either one male with several females or, in a longer tank with lots of cover, a larger mix. It is peaceful toward other species, though males lock jaws and wrestle over space, and in a small tank these bouts can cause injury, so give them room and sight breaks with floating plants. It feeds at the top on small insects and larvae, so offer frozen and live foods along with a floating flake. It likes hard, neutral water and does well with a little salt, matching its part-brackish home. Give a group a covered tank of 95 liters or larger, since it stays at the surface and jumps.
In the wild
Dermogenys pusilla lives across Southeast Asia in fresh and brackish waters, from rice paddies and ditches to slow rivers and coastal creeks. It is used to warm, hard water, so keep a temperature between 24 and 28 C and a pH from about 6.5 to 7.5, with a little marine salt if you like. A tank with floating plants, open surface and gentle flow suits it, and a tight lid is essential for this surface-hugging jumper. Calm, clean water helps it settle.
Good to know
The wrestling halfbeak is a livebearer in the halfbeak family Zenarchopteridae, reaching about 7 cm, with the long lower jaw that gives the group its name. The male fertilizes the female internally using an andropodium, a modified anal fin, and she carries the young until they are born free-swimming. Broods are small and the delicate fry are easily lost, so it is one of the harder livebearers to breed reliably.
Did you know
The name comes from the way rival males grip each other by the beak and shove in trials of strength, contests that hobbyists in parts of Southeast Asia have long staged as a form of fish fighting.
Weekly picks
Tank mates
Wrestling halfbeak is a mostly peaceful, social species that keeps to the top. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Annam hillstream loach
Annamia normani
Freshwater3.7 in (9.4 cm) · 25 gal (95 L)68–77°F (20–25°C)
Croaking gourami
Trichopsis vittata
Freshwater2.8 in (7 cm) · 25 gal (95 L)72–82°F (22–28°C)
Spotted hatchetfish
Gasteropelecus maculatus
Freshwater3.5 in (9 cm) · 26 gal (100 L)73–82°F (23–28°C)
Burmese stone loach
Balitora burmanica
Freshwater3.9 in (10 cm) · 25 gal (95 L)68–79°F (20–26°C)
Lake Wanam rainbowfish
Glossolepis wanamensis
Freshwater3.9 in (10 cm) · 25 gal (95 L)77–86°F (25–30°C)
Spotfin hatchetfish
Thoracocharax stellatus
Freshwater3.5 in (9 cm) · 26 gal (100 L)73–82°F (23–28°C)
Common questions
What size tank does a Wrestling halfbeak need?
A Wrestling halfbeak needs at least 25 gal (95 L). It spends most of its time in the top.
What temperature and pH does a Wrestling halfbeak need?
A Wrestling halfbeak is comfortable at 75–82°F (24–28°C) with a pH of 6.5–7.5.
How big does a Wrestling halfbeak get?
An adult Wrestling halfbeak reaches about 2.8 in (7 cm).
Related species
3.5 in (9 cm)40 gal (150 L)68–77°F (20–25°C)Celebes halfbeak
Nomorhamphus liemi
3.5 in (9 cm) · 40 gal (150 L)
3.5 in (9 cm)29 gal (110 L)75–81°F (24–27°C)Redfin halfbeak
Nomorhamphus ebrardtii
3.5 in (9 cm) · 29 gal (110 L)
2.6 in (6.5 cm)14 gal (54 L)73–81°F (23–27°C)Gold-spotted halfbeak
Hemirhamphodon chrysopunctatus
2.6 in (6.5 cm) · 14 gal (54 L)
2.6 in (6.5 cm)14 gal (54 L)73–81°F (23–27°C)Red line halfbeak
Hemirhamphodon phaiosoma
2.6 in (6.5 cm) · 14 gal (54 L)
2.4 in (6 cm)14 gal (54 L)73–81°F (23–27°C)Fire halfbeak
Hemirhamphodon kapuasensis
2.4 in (6 cm) · 14 gal (54 L)
3.3 in (8.5 cm)20 gal (75 L)73–81°F (23–27°C)Kuekenthal's halfbeak
Hemirhamphodon kuekenthali
3.3 in (8.5 cm) · 20 gal (75 L)
