Shortfin Molly
Poecilia mexicana
Brackish Central America Usually captive bred
A wild-type livebearer sporting subdued silvery-green tones with light iridescent spotting. Extremely hardy, it flourishes in hard alkaline freshwater or brackish setups. Provide vegetable-based flakes and algae to maintain its health, and keep in a ratio of several females to each male.
Also called: Atlantic molly, Orangefin molly, Shortfin molly.
Try it in the planner Opens a tank sized to its minimum with 1 fish added.
What it needs
| Item | Value | Because |
|---|---|---|
| Adult length | 8 cm | Used for the Space check: the tank must be long enough for the fish to turn round. |
| Smallest tank | 80 L, at least 60 cm long estimated | The least water and floor length this species is kept in for good, as a single fish or smallest group. |
| Extra water per added fish | 10 L estimated | What each further fish adds once the minimum is met. |
| Waste load | Class 2 of 5 estimated | How much waste an adult makes against its size. Feeds the Load check. |
| Temperature | 22 to 28 C | Stock sharing a tank need overlapping ranges. |
| pH | 7.2 to 8.5 | Compared with tankmates in the Water check. |
| Hardness | GH 10 to 25, KH 6 to 15 | Degrees of general and carbonate hardness. |
| Flow | Low | Low-flow fish are stressed in a strong current. |
| Light | Moderate | Matched to the lighting class on the needs sheet. |
| Group size | Single fish is fine | Not a schooling species. |
| Temperament | Peaceful | Not territorial. |
| Swims in | Upper water | Fish that use different levels share a tank more easily. |
| Lifespan | About 4 years | A fish is a long commitment. |
| Experience | Suits a first tank | A guide to how forgiving the species is of mistakes. |
| Jumps | Yes | Keep the tank covered. |
Tags marked estimated are judged from the size and habits of the species rather than measured, so treat them as a sensible default.
Diet and tank layout
Shortfin Molly is an herbivore that swims in the upper water. It is safe with plants. Give it some cover.
Tankmates
Works with
Depends
Compare any two fish on the compatibility page, or print the equipment for a stock on the needs sheet. How this is worked out: the method.