Sam Borstein's Cichlid Page

Poecilia sphenops
Valenciennes, 1846

Mexican Molly, Sphenops Molly

Mexican Molly
Above: A female Mexican Molly. Photo by Sam Borstein.


Genus- Poecilia= many colors (Greek).
Species- sphenops= wedge appearence (Greek).


The Mexican Molly is another classic in the hobby. This undemanding fish, which does well with a little bit of salt added to the tank is slightly aggressive but works in a community tank.

Here are some popular variants:

It is relatively hard to find wild Sphenops Mollies, but if you do, get them, they are just a beautiful.


This fish is found in lakes, rivers, and pools of Mexico. This fish has a tolerance for brackish water.

Size, Maturity, and Sexual Dimorphism:

Size: Males- 3 inches, Females- 4 inches
Maturity: 2 inches
Sexual Dimorphism: Males are smaller than females. Males also have a gonopodium.


Mexican Mollies are easy to keep. It can be kept in small tank, like a ten gallon with minimal issues, although a 20 gallon community is recommended. This fish is prone to Ich, especially many of the line bred forms, so adding salt is beneficial for this species.


These fish will eat anything. A mix flake is recommended. I like to feed both spirulina and a protein rich flake.


This fish poses no problems when it comes to breeding. It is a livebearer and older females give birth to large spawns. This fish is harder to spawn than Guppies and Swordtails, but still poses few issues.

Parents will chase the fry, so either separate them or provide plenty of cover. The fry are not problematic when it comes to raising them and will gladly accept crushed flake or baby brine shrimp.


This is a good beginner's livebearer, but I recommend keeping Swordtails and guppies first. This is a pet shop fish and should not be hard to find. Wild types are difficult to find though and will require some effort to obtain.