Shortfin Molly

Poecilia sphenops

Shortfin Molly (Poecilia sphenops) — Easy care, Semi-aggressive, under Livebearer & Killifish. Minimum tank in the app: 32 US gal min; aim for 72–82°F and pH 6.8–8.2. Shortfin Mollies are a fantastic choice for aquarists seeking dynamic and visually appealing fish that thrive in groups.

Shortfin Molly (Poecilia sphenops) in a planted freshwater aquarium
Care levelEasy
TemperamentSemi-aggressive
Min tank size32 US gal min
pH range6.8–8.2
Temperature72–82°F
Max size4.3 in (11.0 cm)
Captive lifespan2–4 years
SchoolingYes · 6+ recommended

Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.

Natural distribution

Americas / Africa (varies)

  • Africa
  • South America
  • Central America & Mexico

Regional colours match the stocking calculator’s origin map.

Shortfin Molly Tank Setup

A well-designed tank for Shortfin Mollies should strike a balance between open swimming space and plenty of hiding spots, ideally using plants and decorations to create visual barriers. A gentle water flow mimics their natural habitats, while a substrate of fine gravel or sand allows for comfortable movement. Lighting should be moderate, enhancing their coloration without overwhelming them.

What Do Shortfin Mollys Eat?

Shortfin Mollies are omnivorous and can adapt to a variety of diets, though they thrive on a mix of high-quality flake foods, frozen, and live offerings. They can be competitive feeders, so ensure that food reaches all individuals by providing multiple feeding spots.

Shortfin Molly Tank Mates

Ideal companions include similarly sized and tempered species, such as guppies or rasboras, which share the same swimming zones and dietary preferences. Caution is needed with more aggressive species that may outcompete them for resources. Within their own species, keeping at least six is essential to prevent aggression and establish a harmonious social structure.

Are Shortfin Mollys Good for Beginners?

In App-aquatic we file this under easy care. That still means a cycled tank, realistic stocking, and parameters that do not swing every weekend. A common error is underestimating their social needs; failure to keep them in groups of at least six can lead to stress and aggression. neglecting water quality parameters, especially pH and temperature, can result in health problems.

Building a community? Run the full list through the stocking calculator before you add anything else.

Log tests and reminders in App-aquatic—free, same data you see here.