Micropoecilia minima

Male Poecilia cf "obscura". Schories, Meyer & Schartl, 2009. Photo by Rick Borstein

Common Names: None

Synonyms: Poecilia obsucra, Poecilia minima

Meaning of Name

Genus- Micropoeicilia= Small Variegated Fish
Speciesobscura= not known or not seen


Poecilia cf "obscura"is a very small fish which is highly variable in appearance. Males get up to a tad over an inch long and females approach 1.5". Females are drab fish, but males aren't bad looking, depending on the lighting. Males may have a blue-black dot on the side with splotches of orange, red or green. The color may extend into the tail, but unlike fancy guppies, the color never completely covers the caudal fin.

Originally, this fish was distributed in the midwest as Micropoecilia minima from stock obtained from Alan Wood of Pueblo, Colorado, who had been maintaining it for some time. Subsequently, communication with Mike Hellweg brought to light that this fish is most likely a color form of Poecilia obscura:

P. minima is a really tiny fish [with] males [which] barely top a half inch, and females are about the size of an adult male P. obscura - just barely an inch. They are also fairly gracile in body as opposed to the stouter body of P. obscura. P. minima males are pretty much monomorphic, with all males showing pretty much the same color pattern, just with dominant fish having more intense colors. P. obscura males are very polymorphic, with each male showing a similar colored, yet different pattern. P. minima males have a single black triangular blotch at the base of the caudal peduncle that has red/orange/yellow around it, and they have black bars on the side from just behind the pectoral fin to just in front of the dorsal fin. Males also have a bit of amber over the black bars, and a bit of orange from behind the dorsal fin to the basal spot. Females have these markings, minus the red/orange/amber/yellow. Fry are born with the black blotch on the caudal peduncle, and the black barring shows up in a few weeks. The fry of P. obscura are gray, without any spots or color when born. The color shows up in the males as they reach puberty. P. obscura does. P. minima males have a trailing dorsal fin that reaches back to the caudal fin, too.

I believe some of the confusion may also be attributed to that fact that this fish has different coloration than the other (perhaps only) most often encountered location for Poecilia obscura which is "La Seiva River" which were collected in 2008. Compared to the La Seiva fish, this color form is quite a bit nicer looking. 

Whatever the case, it should be not be distributed as Micropoecilia minima, so if you see them at an auction, you might want to correct the bag.


Poecilia cf "obscura"is is found in Trinidad. We do not know the precise location for this color form.

Size, Maturity, and Sexual Dimorphism

  • Sexual Dimorphism: Males are smaller, more colorful and have a gonopodium
  • Sexual Maturity: 1  inches
  • Size, Male: 1=1.25 inches
  • Size, Female: 1.5 inches


Poecilia cf "obscura"is easy to keep. A group of 20-30 fish may be kept in a 5-gallon or larger tank. Although they will do OK at room temperature, reproduction is more consistent at higher temperatures. I kept mine at 78F in hard Chicago water.


In the wild, Poecilia species are micro-predators which feed on tiny plankton. In the aquarium, these fish will feed on any good quality flake food. 


I obtained five fish from Alan Wood of Pueblo, CO. Alan has been active in the American Livebearer Association for many years and my visit to his fishroom was remarkable. He had many interesting fish. I am a fan of small livebearer, and had never seen Poecilia cf "obscura"before, so I just had to have them. In all, I had five juvenile fish which I housed in a 5-gallon tank. 

The tank had a sand substrate and was filtered by a four-inch Swiss Tropical Poret Foam filter. I performed weekly water changes of two-thirds of the tank volume and the fish grew steadily. At the top of the tank, I added a plastic plant mat to help conserve fry.

It wasn't long before I saw the first tiny fry. The babies are unmolested by the parents and my population grew quickly. For optimal growth of the tiny fry, provide live or frozen baby brine shrimp.


This diminutive fish is easy to keep, pretty and unusual. It's a great fish for kids or anyone who wants to work with a livebearer that thrives in small tanks.