Atlantic Molly Care Guide
The Atlantic molly (Poecilia mexicana) is a hardy Central American livebearer tolerant of fresh, brackish and even hypersaline water.
Overview
Poecilia mexicana, the Atlantic molly, is a livebearing fish described by Steindachner in 1863. FishBase lists a maximum standard length of about 11 cm, with females larger and deeper-bodied than the more slender males. The body is brown above and grades to golden-yellow below.
Taxonomy
- Family: Poeciliidae
- Genus: Poecilia
- Scientific name: Poecilia mexicana
- Described by: Steindachner, 1863
Habitat
The species occurs on the Atlantic slope of Middle America, from the Rio San Juan and the Rio Bravo basin in Mexico south through Central America. According to FishBase it inhabits warm springs and their effluents, canals, weedy ditches and stream pools. It tolerates fresh, brackish and salt water, with reported salinities up to about 32 ppt, and two notable cave populations live in sulphidic, oxygen-poor water containing hydrogen sulfide.
Tank requirements
- Minimum tank volume: 100 L
- Temperature: 22-30 °C (72-86 °F)
- pH: 7.5-8.5
- GH: 12-30 °dGH
- Lifespan: 3-5 years
- Water: hard, alkaline; tolerates brackish conditions
Diet
The Atlantic molly is an omnivore. FishBase notes that its food is mainly detritus, and Wikipedia describes it feeding chiefly on algae and detritus, including filamentous algae and diatoms scraped from surfaces. In aquaria it accepts vegetable-based flakes and benefits from algae grazing.
Compatibility
This is a peaceful, mid-water fish suited to hard-water community tanks. It does best with other hard-water species and other mollies, and should not be combined with soft-water fish whose requirements conflict with its preference for alkaline, mineral-rich water.
Breeding
Poecilia mexicana is a livebearer. FishBase reports that females give birth to roughly 30-80 young about 28 days after fertilisation and reach sexual maturity at 7-12 months. Breeding occurs year-round, and males use forced mating rather than elaborate courtship.
Conservation status
IUCN Red List: Least Concern (assessed 22 March 2018).