Male Poecilopsis gracilus Heckel 1848

Common Name: Porthole Livebearer
Synonyms: None

Meaning of Name

Genus- Poecilia= many colors (Greek), opsis= appearence (Greek)
Species- gracilis= slim (latin)


Poeciliopsis gracilis is a small and peaceful livebearer from Central America. The common name "Porthole Livebearer" was undoubtedly bestowed because the round black markings on the flank of the fish are reminiscent of portholes on a ship. Although not particularly colorful, this species has nice markings and is an active swimmer.

Both males and females have slivery-gold base iridescent base color overlayed with four or five dark, round spots which are nearly perfectly round.

Poeciliopsis gracilis is incredibly prolific, so be prepared to share lots of fry with friends.


This fish is found along the Atlantic coast of Mexico, Guatemala and Honduras, usually in slow moving water such as ditches and irrigation canals. Introduced populations have been found in Central Mexico, Venezuela and even the United States (California). Water conditions for native fish vary widely from 6.5 to 7.8 pH.

Size, Maturity, and Sexual Dimorphism

Size: Males- 1.5 inches, Females 2.5 inches
Maturity: .75 inch
Sexual Dimorphism: Males are much smaller and slimmer than females. Males have a gonopodium.


Poeciliopsis gracilis is easy to keep. These fish will live and reproduce in very small tanks. I kept mine in a 5-gallon tank and had hundreds of fry. I performed regular partial water changes of 50% of the tank volume weekly. My water conditions are typical of Chicago (very hard).

These fish seem to tolerate a wide range of temperatures. I think they would be happy anywhere from 68F to 85F.

Poeciliopsis gracilis do occasionally jump, so be sure to cover the tank.

In small tanks, males will constantly pursue females which will be in a near constant pregnant state.

As an experiment, I pulled out three one-inch females to use as dither fish for a timid group of Apistogramma (cichlids). Over the course of the year, without the constant pursuit of a male, the females grew at an incredible pace, getting up to 2.75" inches. I later introduced a small male to the tank and he was unable to successfully copulate with the much larger females.


Poeciliopsis gracilis will thrive on any good quality flake food. I fed Aquarian Community Flakes and also HBH Graze. They also love to eat baby brine shrimp and microworms.


I obtained a dozen Poeciliopsis gracilis at the 2009 ALA Convention. I think I paid five bucks. When I asked if they were easy to breed, the vendor told me that if I couldn't breed them, I didn't deserve to be in the hobby. "Just like guppies, but easier."

My kind of fish!

I brought the fish home and placed them in a five-gallon tank containing a bit of java moss and a sponge filter. My tank temperature was 76F. Sure enough, within a couple of weeks I had babies. The adults do not pursue the fry.

In my experience, females will drop anywhere from six to fifteen babies. I suppose very large females might have larger broods.

The fry are easy to raise in the same tank as the adults. The babies will eat finely crushed flake food, but will get a faster start if provided with freshly hatched baby brine shrimp or microworms.

Some cichlid breeders keep this fish as a live food source, but I've always been successful in giving the fish away or selling them.


Poeciliopsis gracilis is an attractively marked, easy to keep fish. Porthole Livebearers are great fish for kids since success is pretty much guaranteed. They are often readily available at bargain prices, too!


Poeciliopsis gracilis Female