Photo thanks to Aquasaur - female

Name:
Scientific name: Poecilia sphenops
Common name: Black Mollie
AKA: Black Molly/ Common Molly/ Mexican Molly/ Molly/ Short-finned Molly
Mistakenly or previously labelled:

Country of origin: South to Central America

pH: 7.0 – 8.5
Temperature: 21 - 28c
Hardness: 15 – 30dGH
Water flow: standard
Oxygenation: high

Maximum size: 8 cm – male; 12cm - female

Diet: Live, frozen, flake & (sinking) pellet foods – an omnivore. They need a large proportion of vegetables in their diet – such as blanched peas, spinach, spirulina or algae wafers.

Breeding:
Males: Smaller, more colourful, modified (pointed) anal fin
Females: Larger, duller, standard anal fin

They are livebearers, breading readily and prolifically. The females are capable of mating once in a lifetime, then storing the sperm to be used every time they spawn (about once every 35 days).

The males will relentlessly pursue the females, so it is best to keep at least 4 females per male.

They will eat their own and each other’s fry, however even with this predation the population can quickly overrun even a medium sized tank, so plans should be made for disposing ethically of the offspring (e.g. taking them to a willing Local Fish Store).

To ensure the fry survive, provide floating and dense vegetation.

They are able to interbreed with other molly species, particularly P. latipinna, so only one mollie species should be kept per tank.

Lifespan: 3 - 5 years

Tank companions:
They are NOT good tank companions with shrimps.

They are a schooling species. They should be kept in groups of 6+, with more females than males, in order to spread the aggression.

Although they are boisterous, they are generally peaceful with other tankmates. They can manage more boisterous tankmates, and should not be kept with very shy fish.

As with any fish they will eat any fish small enough to fit in their mouths, and equally can be eaten by any fish large enough to eat them. This should be taken into account when choosing tankmates.

Stocking plans can be checked with aqadvisor.com

Tank:
Minimum tank size is 3 ft for a small group. More room is needed for a larger group and/or tankmates. Bear in mind when planning your tank size and stocking levels, that they are prolific and frequent breeders.

They could be kept in a heavily planted tank with floating plants to subdue the lighting and open areas for swimming, or a biotype with sand (or 2Tone’s DIY substrate), driftwood and tannins from Indian Almond Leaves.

They do best in brackish, rather than fresh water and can be found naturally in both brackish and marine environments. They are commonly used to cycle marine tanks. Although they can be transferred into more salty conditions fairly rapidly, they should be acclimatised back to fresher water very slowly, as it will put more pressure on their kidneys.

Confused with:
There are other recognised species in the genus known as mollies, all of which are allowable imports to Australia:
Poecilia latipinnis – sailfin molly – long dorsal fin
Poecilia sphenops – black molly – short dorsal fin
Poecilia velifera – giant sailfin molly – long dorsal fin & large size

There are colour morphs & variations in form, some of which are crosses with P. latipinnis:
Balloon – caused by a deformity of the spine, which does not allow enough room for the internal organs, resulting in premature death
Black – black colour
Dalmation – white with black spots
Gold - yellow
Green – a silver/green with iridescent scales speckling the body
Lyretail – elongations on the top & bottom of the tail
Silver – a silver/ white colour

There are introduced (feral) populations in many countries, including Japan, Singapore and parts of Eastern Europe.

Wild fish are very rare in the trade, with the majority being commercially bred. The extent of this breeding has made a previously very hardy fish more prone to disease (particularly the black colour), but they are still a good choice for beginners.

Poecilia sphenops are legal imports to Australia as of 12/11/2013 (list last updated 16/10/13).
http://www.environment.gov.au/system...mport-list.pdf

The IUCN Red List reports Poecilia sphenops as a species which has not yet been assessed, at 06/01/2013:
http://www.iucnredlist.org/search

It is very important not to release any aquarium specimens into our waterways. Any that are not sold or re-homed/ given away, can often be re-sold to aquarium stores. If they are homed in ponds, care should be taken that they cannot escape in run-off into our waterways. Even if fish are native & local they should not be moved from one waterway to another, as this can transfer disease. If they are not local fish, they can both spread disease and either out-compete or eat local fish, shrimp & plants, causing their demise.

They are good fish for beginners.

Relevant threads:

Breeding:
http://www.aquariumlife.com.au/showt...ighlight=molly

Salt water/ brackish water:
http://www.aquariumlife.com.au/showt...ighlight=molly

Hard, not soft water:
http://www.aquariumlife.com.au/showt...ighlight=molly

Do not keep with bettas:
http://www.aquariumlife.com.au/showt...ighlight=molly

References:

Fishbase:
http://www.fishbase.org/summary/4680

Seriously Fish:
http://www.seriouslyfish.com/species/poecilia-sphenops/

Wikipedia:
http://en.wikipedia.org/wiki/Poecilia_sphenops

Pics & threads with pics:


Photo thanks to Aquasaur - pair


Photo thanks to Whiteslea – female Dalmation lyretail Poecilia sp.


DE
06/01/2014