Dusky Millions Fish

About

The Dusky Millions Fish (Phalloceros caudimaculatus) is a small South American livebearer native to coastal drainages from Rio de Janeiro south through Uruguay and into Argentina, where it occupies a range of slow-moving and still-water habitats. It has also been widely introduced elsewhere for mosquito control, though at least some introduced populations have caused ecological problems. One of the more interesting things about this species is how variable it looks. Three distinct ornamental forms circulate in the hobby, including a spotted variety, a golden form, and a spotted golden combination, each sometimes listed under unofficial hobbyist names. Both golden forms appear less robust under natural conditions, which is worth keeping in mind. Despite its small adult size, this fish is tagged as intermediate care, largely because the males can be relentless in harassing females. Keeping a higher ratio of females to males goes a long way toward reducing that stress. A species-only setup is generally the better approach rather than mixing it into a community. Breeding is fairly straightforward for a livebearer. Gestation runs roughly four to six weeks, and fry that arrive into a densely planted tank with well-fed parents have a reasonable chance of surviving. The genus itself underwent a major taxonomic revision in 2008, so what was once a single-species group now contains over twenty described species.