Girardinus metallicus (Poey, 1854)
Etymology: Girardinus after the French – American ichthyologist Charles Girard
metallicus referring to the metallic body colouration.
First description: Poey F. 1854.
Los guajacones, poecesillos de agua dulce. In Poey, F., Memorias sobre la historia natural de la Isla de Cuba.
Havana, vol. 1, pp 374 – 392, figs 8-11.
Common name : Metallic livebearer, Metallic Topminnow
Synonyms: Girardinus garmani Eigenmann 1903
Girardinus pygmaeus Rivas 1944
Type Locality: Botanic Gardens, Havana, Cuba.
Distribution: Costa Rica, Throughout Cuba, except easternmost area at 200-300 m elevation.
History: Reports suggest the first import for the aquarium trade was made in 1906 by W. Schroot of Hamburg.
Habitat: It can be found in streams, ponds and ditches. The water is commonly stagnant and often brackish.
Inhabits ponds, lakes and streams. Prefers clear, stagnant or very sluggish water.
Size: Male 5.0 cm, Female 9.0 cm
Description Girardinus metallicus has a streamlined head and body with a superior mouth. The dorsal, pectoral, and caudal fins are medium length and rounded. Females have longer, deeper, more rounded bodies than the males with rounded anal fins.
Colour/Pattern: There are two known colour variants for this species the better known ‘black-chin’ and a gold belly form.
Black chin – males have a black line starting from the mouth from the mouth and continuing through the underside of the body (including the gonopodium) and can reach the caudal fin, some specimens can have further black colouration which in some circumstances envelopes the whole head.
Gold form – males have a gold underside extending from the rear of the belly to the caudal peduncle.
The females for both variants look the same,
Bodies and heads range between translucent silver to a pale gold to olive colour. Iridescent silver diamond-shaped bars along the lateral line.
Dorsal fin has a black spot at the bottom centre of the dorsal fin. Males have a deep overall metallic gold sheen, making the silver diamonds appear brighter and larger than on the paler female.
Behaviour: Peaceful, will predate fry. Likes to swim in the upper part of water column
Husbandry: Water should be medium hard and alkaline with a gentle flow, a sponge filter or something of that ilk is perfect. A temperature of 24º to 26º should be aimed for
Girardinus metallicus are omnivores and enjoy live or frozen foods, supplemented with algae flakes and small pellet food.
A well planted tank comprising of a substrate of sand/gravel and plenty of surface cover will help this fish to acclimatise and feel secure. Hiding places will also be advantageous.
Breeding Notes: As with other poeciliid species, the males are known for their persistent behaviour so a ratio of at least 2 females per male is recommended.
Gestation takes around 24 – 28 days and broods of between 15-30 fry can be expected and adult fish will predate on the young so plenty of plant cover is required to provide shelter for the fry.
References: Wischnath, L., 1993 – Atlas of livebearers of the world.
Seriously fish www.seriouslyfish.com
Lee, D.S., S.P. Platania and G.H. Burgess, 1983. Atlas of North American freshwater fishes