Half Black Guppy

Looks how to spot one

Scales and fins

The Half Black Guppy has a sleek, streamlined body typical of guppies. Males are smaller with long, flowing fins and a striking pattern where the rear half of the body is deep black or dark blue, while the front half is bright yellow, orange, red or metallic. Females are larger, with shorter fins and a more subdued grey or silver body marked with black spots.14

Personality what they are like

Half Black Guppies are peaceful, social and active fish. They enjoy swimming in open areas and males often display courtship behaviour. They are generally safe in community tanks, but should not be kept with fin-nipping or aggressive fish, as their long fins can be damaged.53

Daily activity how busy a day looks

They are active swimmers and need open swimming areas. A well-planted aquarium with floating plants and gentle water movement suits them best. Avoid excessive water flow.3

Grooming and care the hands-on bits

Grooming is not applicable, but regular water changes and good filtration are essential. Keep the water clean and stable, with moderate lighting and a fine gravel or sand substrate. Provide plants and rocks for hiding.13

Home where they are happiest

Minimum tank size of 10 gallons (about 38 litres), though 60 litres or more is recommended. Water temperature should be 72-82°F (22-28°C), pH 6.8-7.8, hardness 8-12 dGH. They prefer hard water and can tolerate some salinity. Keep them in a guppy-only tank to protect their fins, or with peaceful community fish.146

Food basics what goes in the bowl

Omnivorous. Feed high-quality flakes or micro pellets, plus algae-based foods. Supplement with live or frozen foods such as brine shrimp, bloodworms and daphnia. Feed adults twice a day, and fry three times a day.14

Company who they like around

They are shoaling fish and should be kept in groups. Keep more females than males, about one male to two or three females, to reduce harassment. They are peaceful and can live with other non-aggressive fish, but avoid fin-nippers and large predators.637

The story where it all began

The Half Black Guppy is a colour strain of the common guppy, Poecilia reticulata. It was first bred in Germany in the 1980s by crossing a Black Guppy with a Red Guppy. The strain later gained popularity in America, where breeders developed larger sizes and more spectacular fins. What makes this variety different from the plain guppy is its distinctive pattern: the rear half of the body is solid black or dark blue, while the front half is brightly coloured, often yellow, orange or red. This striking contrast, along with flowing fins in males, makes it a favourite among aquarium enthusiasts.12

Recognised by the official bits

Not formally recognised as a separate species; it is a colour strain of the common guppy.

Half Black Guppies are a popular designer strain of Poecilia reticulata, bred for their distinctive half-black body pattern.3

Popularity Very popular among aquarium hobbyists, especially those who appreciate fancy guppies.4