Halfdark Glassbelly (Ghost Guppy)

A living sliver of glass, half swallowed by shadow.

The Halfdark Glassbelly Ghost Guppy is a peaceful 2.5–3.5cm livebearer with a translucent belly and striking dark rear, perfect for planted nano communities.

• Water conditions: The Halfdark Glassbelly (Ghost Guppy) is a freshwater livebearer that does best in a mature, fully cycled aquarium with stable parameters. Aim for a temperature of 22–28°C, pH 6.8–7.8, general hardness around 8–16 dGH and carbonate hardness around 3–8 dKH. Ammonia and nitrite should always read zero, and nitrate is best kept below 20–30 ppm through regular water changes and sensible stocking. These guppies appreciate moderate oxygen levels and gentle to moderate water flow rather than strong current, so a sponge filter, small canister or baffled internal filter works well. A tank of around 40 litres or more is suitable for a small group, with more space helping to keep water quality stable. Use a reliable heater and thermometer, and top the tank with a lid because guppies can jump. Test water regularly, acclimatise new arrivals carefully and avoid sudden swings in temperature or pH, as stability matters more than chasing exact numbers.
• Suitable tank mates: Because this strain is peaceful, it mixes well with other calm community fish of a similar or slightly larger size. Good options include small tetras, micro rasboras, Corydoras catfish, Otocinclus, peaceful pencilfish and other non-aggressive livebearers. Small snails can also work well, while shrimp may be safe with adults but shrimplets can be eaten, so plan accordingly. Avoid fin-nipping species such as some barbs, large or predatory fish, aggressive cichlids, goldfish, crabs and any tank mate big enough to see the guppies as food. Betta compatibility depends heavily on the individual fish and tank size, so it is not a guaranteed safe pairing. Keep guppies in a group rather than singly; a ratio of one male to two or three females is ideal if you plan to breed, while single-sex groups can help prevent unwanted fry. Always quarantine new fish before adding them to a display tank.
• Feeding habits: The Halfdark Glassbelly is an omnivore with a small mouth, so offer foods sized for nano fish. A high-quality micro pellet or crushed flake should form the base of the diet, supplemented with live or frozen daphnia, baby brine shrimp, cyclops and occasional bloodworm. Include spirulina or vegetable-based foods to support digestion and condition. Feed two or three small portions daily, offering only what the group can clear within about two minutes, and remove uneaten food to protect water quality. A weekly fasting day can help prevent overfeeding and bloating. Variety is important: a monotonous diet can lead to poor colour, weakened condition and breeding problems. Because glassbelly strains show their internal area more clearly, avoid heavy feeding that leaves the belly overly distended, and watch for changes in appetite or body shape as early signs that something needs adjusting.
• Care requirements: Provide a well-planted aquarium with floating plants, gentle flow and open swimming space. The translucent belly and dark rear half make this strain especially attractive against a dark background and green foliage, but avoid sharp decor that could injure delicate fins or the body. Acclimatise carefully using the drip method over 30–45 minutes, and quarantine new fish for two to four weeks where possible. Carry out weekly water changes of around 25–30%, vacuum the substrate, rinse filter media only in tank water and keep the heater and filter running reliably. These are livebearers, so if males and females are kept together, expect fry; provide cover such as moss or floating plants for survivors, or separate sexes if you do not want breeding. Observe the group daily for clamped fins, laboured breathing, white spots, wasting or unusual belly appearance, and act early with parameter checks and isolation if needed. With stable water, varied feeding and peaceful company, this 2.5–3.5cm guppy makes a lively, elegant addition to a carefully planned community tank.