Rainbow Goodeid, Red Prince
Endemic to the state of Durango, Mexico.
It’s mainly found in clear, stony-bottomed springs and streams. These are usually heavily vegetated.
Maximum Standard Length
Male 1.6″ (4cm). Female 2.2″ (5.5cm).
Aquarium SizeTop ↑
You could keep a couple of pairs of these in a standard 24″ x 12″ x 12″ (60cm x 30cm x 30cm) – 55 litres tank.
A planted aquarium with a substrate composed of large gravel and/or small pebbles would resemble its natural habitat. A cover of floating plants is also recommended. The water must be kept scrupulously clean, so efficient filtration and frequent small water changes are essential. Any algal growth can be left alone, as the fish will graze on it.
Temperature: 62-75°F (17-24°C). The temperature should not be allowed to rise above 75°F. This is a subtropical species and will appreciate a temperature drop over the winter months.
pH: 6.5-8.0. Preferably on the alkaline side of neutral.
Omnivorous and unfussy. The diet should contain live and frozen foods along with some vegetable matter such as blanched spinach or vegetable flake for the best conditioning.
Behaviour and CompatibilityTop ↑
Not the easiest livebearer to breed, as initial broods may die for no apparent reason. Flock spawning (in which the fish are maintained and bred in groups) is the best method to establish a viable population. The breeding tank should contain lots of plants. Goodeids breed in a slightly different way to other livebearers. Females do not store sperm as in many other livebearing species and must mate separately for each brood of young. They also display no gravid spot.
Gestation takes between 55-60 days after which 5-20 very large fry are produced. Sometimes these may have what appears to be an umbilical cord attached. This is quite normal (see below) and will disappear in 2-3 days. The fry are large enough to accept the same foods as the adults from birth. The parents rarely predate on them. Breeding appears to be seasonal as after a couple of broods a female may not produce any more young for 6-8 months.
Recommended only to the expert fishkeeper. This can be a difficult livebearer to maintain in the aquarium. Entire groups of fish may suddenly die without warning. It is very sensitive to high temperatures and is also disease-prone. This is most likely related to the fact that this fishes’ natural environment of clear streams contain very pure water that is being constantly renewed.
As with other goodeids, there is less of a size difference between the sexes than in many other livebearers. This is thought to be related to the relatively primitive structure of the andropodium, as the fish tend to choose mates that are of similar size so that the sex organs are synchronised.
Goodeids are unique among livebearers in that the developing young are nourished by a specialised structure known as the trophotaenia. This performs a similar function to the placenta in mammals and the remnants of it can often be seen attached to the young fish at birth. Male fish also possess an internal muscular structure known as a pseudophallus, which connects the sperm ducts to the genital opening, which is said to forcibly eject sperm.
Possibly extinct in nature, this species is kept infrequently except by livebearer enthusiasts and usually commands a high price when available. Its precarious natural status means that every attempt should be made to breed these fish should you be lucky enough to obtain some.