Halfmoon Betta

1 Species Overview

The “halfmoon” name comes from the caudal fin, which can spread to a full 180 degrees; when the fish swims, the tail looks like half a moon, giving rise to the common name Halfmoon Betta. There are two judging standards — HM and OHM. HM (Halfmoon) means the tail spreads to 180 degrees; OHM (Over-Halfmoon) means it spreads beyond 180 degrees and is considered the finest grade within HM.

Chinese name: Halfmoon Betta (a name that literally means ‘half-moon fish’). It is also known by several folk Chinese names — such as ‘iron fish’, ‘moon fish’, ‘paradise fish’, and ‘Chinese fighting fish’. Scientific classification: Kingdom — Animalia; Phylum — Chordata; Subphylum — Vertebrata; Class — Osteichthyes; Subclass — Actinopterygii; Order — Perciformes; Family — Osphronemidae; Subfamily — Macropodusinae; Genus — Betta; Species — Betta splendens. Distribution: tropical and subtropical regions, also found in China.

2 Morphological Characteristics

The Halfmoon Betta is divided into HM (Halfmoon) and OHM (Over-Halfmoon). HM means the tail spreads to 180 degrees, shaped like a half moon, while OHM means it spreads beyond 180 degrees; OHM is generally the top grade of HM. Adult fish are usually 8–10 cm long.

Although bettas are naturally aggressive, observation shows that Halfmoons mostly coexist peacefully with small tropical ornamental fish. Their defining feature is a special respiratory organ called the “accessory organ” (labyrinth), used to breathe air — they can gulp a mouthful of air at the surface and pass it into this organ for gas exchange. The body is covered with ctenoid scales; the dorsal and anal fins are elongated, with the spiny portion longer than the soft portion, and the first ray of the pelvic fin extends into a filament. The body is light brown with about ten blue or green transverse bands, two to three dark oblique bands run from the eye to the gill cover, and there is a blue spot at the rear edge of the gill cover. They can live in polluted water of ponds and ditches.

3 Habitat & Living Environment

The suitable water temperature is 20–25°C, and Halfmoon Bettas are not very demanding about water quality — total hardness around 6–8 GH and pH 6.5–7.5 are both fine. Although males easily fight each other, they generally get along with most small tropical ornamental fish.

The container can range from a large community tank down to a small glass bowl, with no special restriction. But because of their combative nature, to avoid serious fighting they are usually kept singly. If you want to keep two males to show off their finnage, place a sheet of glass with a non-toxic plastic board behind it in the middle of the tank — you get a good view without the fish harming each other.

It is recommended to lay a thin, clean layer of substrate or colored sand on the bottom at a water-to-sand ratio of about 5:1; plant low-CO2-demand plants such as Ceratophyllum or Hydrilla; and provide ample light, preferably a small soft-light fixture for a small glass tank.

4 Feeding Guidelines

The Halfmoon Betta is relatively easy to keep, not demanding about water quality, and is an omnivore that leans carnivorous and is not picky — so what to feed is a common question among keepers.

As an omnivore leaning carnivorous, it can be fed brine shrimp, tubifex worms, daphnia, and similar live foods. Feed only what it can finish within about five minutes, once a day. Healthy specimens captured from wild shallow weedy water or bought from a shop can all be hand-fed; bettas adapt well and are easy to keep. Fill a prepared glass tank with clean river or pond water, or tap water that has stood for at least a day, and place the fish in — but do not fill the tank too full, or the betta may jump out. You can add stalactite stone or pebbles to give it hiding places. A tank can hold two or more pairs for viewing.

Bettas eat a wide range of foods: bread crumbs, steamed-bun crumbs, meat scraps, bloodworms, chopped earthworms, and plankton are all favored. Feed each adult about 0.3–0.5 g per day in 2–3 small meals. Change the water every 7–10 days, but during breeding change only half the volume at a time, using a siphon to carefully remove debris from the bottom so you do not break the bubble nest or suck up the fry. After hatching, the fry cluster at the surface and should be netted into a small separate tank. Feed them finely ground boiled egg yolk mixed with water, a small amount per tank per day; too much spoils the water. Also add matured green water (with planktonic algae), or raise the fry directly in it. Change water every 4–5 days, again half the volume, and filter the siphoned dirty water through cloth so the tiny fry are not lost.