Rare swordtails aren't sold often in the UK outside specialist circles. Matt Clarke managed to find these on sale in Dundee.
Common name: Pygmy swordtail
Scientific name: Xiphophorus multilineatus
Origin: Endemic to the Rio Coy, Mexico.
Habitat: Fast-flowing sections of the Rio Coy, a rocky, clear water river.
Water: Very hard and alkaline water, pH 7.0-8.0; 22-26C/711/2-78F. It's said to be quite tricky to keep - make sure the water quality is spot on.
Diet: Wild fish feed on aufwuchs, algae and zooplankton, but aquarium fish should take live/frozen Daphnia, frozen brine-shrimp and flake foods.
Aquarium: A rocky, boulder -filled tank with clean, moving water. Sometimes found in weedy areas, so plants would fit the biotope.
Breeding: A livebearer, it produces broods of 10-20 fish after a gestation period of three to four weeks.
Similar species: Previously considered a race of X. nigrensis, it is now a species in its own right and has around four morphs which vary in male size and colour. It could be confused with X. pygmaeus and X. nigrensis. All three of these Pygmy swords have a golden-yellow form. However, these are so rarely seen that any on sale are likely to have come from a specialist breeder who confirmed their identity.
Availability: Rarely seen outside specialist livebearer associations. These were on sale at The House of Pisces in Dundee.
Price: 5 each.
This article was first published in the September 2004 issue of Practical Fishkeeping magazine.