Shortfin Molly

About

The shortfin molly (Poecilia mexicana) is the species lurking behind most of the fancy mollies sold in the hobby, though the wild form itself rarely gets the attention it deserves. Native to a stretch of North and Central America running from the Rio San Juan in Mexico down into Guatemala, this fish is remarkably adaptable in the wild. Turning up in warm springs, weedy irrigation ditches, slow stream pools, and even underground cave systems. That flexibility in nature translates reasonably well to the aquarium, though its intermediate care rating reflects a need for stable, hard, alkaline water and enough space to move around. Like other mollies, this species leans heavily on plant matter and organic debris as food sources in the wild, so a diet with good vegetable content keeps them in better condition than a purely protein-based menu. Behavior is generally peaceful and social, making the shortfin molly a workable community fish when tankmates are chosen thoughtfully. One thing worth knowing: this species has established feral populations outside its native range in at least one country, which is a useful reminder about responsible disposal of any livebearers you no longer want to keep.