Natural history
FishBase reports broods of roughly 10–50 young and maturity at about three months. These values describe the species account rather than a guaranteed brood size or fixed breeding date for every individual. Live birth distinguishes their reproductive strategy from the exposed eggs of many similarly sized stream fish.
The range extends from southern Mexico to Honduras, and occupied habitat includes irrigation canals. Its use of human-made waterways shows that suitable habitat is not limited to natural creek channels. USGS attributes introduced records to possible aquarium release or escape from fish farming.
Sources: Poeciliopsis gracilis species summary; Porthole Livebearer species profile
Guide sources
Research reviewed 2026-10-19.
Diet and feeding
The FishTraits compilation records these diet categories for this species: algae or phytoplankton; detritus or unidentified plant material; invertebrates or larval fish. These are broad categories, not a claim that every individual consumes every example in a category.
Reported feeding positions include bottom feeding and surface or water-column feeding. The compilation combines published observations; diets can vary with age, locality, and available food.
Habitat preferences
Reported habitat associations include streams and small rivers, creeks.
The source records associations with muck, clay or silt, vegetation. An association indicates reported use, rather than an exclusive requirement.
Reproduction and parental care
The compilation reports a representative maturity age of 0.25 years. Its maturity field summarizes mean, median, or modal estimates, usually for females; male estimates can be used when female data are unavailable. It is not a fixed age at which every fish first breeds.
Batch or serial spawning has been reported somewhere in the species’ range. This does not establish the same spawning pattern for every population.
Recorded spawning months are Mar, Apr, May, Jun, Jul, Aug, Sep, Oct for the source’s reporting region (CA). This is a regional calendar, not a range-wide schedule.
Size and recorded longevity
FishTraits reports a maximum total length of 5.1 centimetres. Some entries use an estimated asymptotic length; this value should not be treated as a certified record catch.
Recorded longevity in the compilation is 1 years. Wild observations were preferred, but captive records were accepted where wild records were unavailable, and unspecified records were assumed wild. The value is not a guaranteed wild lifespan or an aquarium life expectancy.
Native range
Southern Mexico to Honduras on Atlantic and Pacific slopes (Rosen and Bailey 1963; Page and Burr 1991).
Introduction history
Probably due to an aquarium release or escape from a local fish farm (Mearns 1975; Lee et al. 1980 et seq.).
