Thunder336;913897; said:
Thanks for the help.. How can you tell male from female? These will be used to feed my Oscar babbies and adults..
The anal fin on male livebearers like guppys and mollys is tube-like and pointed (i believe it is called the gonopodium or something), while the anal fin on female guppys and mollys is shaped like an open fan. Male mollys may sport a large sailfin, however there are many varieties of mollys and not all males may have this sailfin. Male guppys generally tend to be more colourful than the females, but this is not a strict rule and i have seen many bland coloured/patterned males and many colourful/vibrant looking females. So the most accurate way to tell the genders apart is by the anal fin of the fish, as this never varys in shape or appearance in mature male or female livebearers like mollys and guppys etc.
When female guppys and mollys are pregnant, they will display a dark patch/area near the back of the stomach called the gravid patch/spot- this dark coloured area is actually the fry's dark eyes you are seeing through the thin skin of the female fish. So the more pregnant the guppy/molly is, the darker the gravid patch will become as the frys eyes darken as they grow inside the fishes womb. However some females have thicker skin or stronger colouring than others, so this gravid patch may not always be obvious. I have also seen male guppys with "fake" gravid patches, which are purely the colouring of the fish and nothing more.
Be wary of buying female swordtails when buying female mollys as female swordtails look very similar in shape/appearance to female mollys. Female swordtails tend to be longer and more slender looking, swordtails also come in some colours and patterns which are not present in mollys, like the colour red.
Mollys and guppys can technically crossbreed, but it is very rare and such hybrid fry resulting from such fish tend not to survive or be quite deformed.
Platys and swordtails can easily crossbreed though. However platys and swordtails cannot crossbreed with guppys and mollys or vice versa etc.
When you go to buy the female guppys/mollys, try to avoid heavily pregnant ones or ones which look like they have just given birth, as they will be very stressed at this stage and be more difficult to successfully acclimatise to the tank (ones which have just given birth may fall ill and die from the stress, and heavily pregnant ones may abort/miscarry their fry if put under too much stress from being taken from the lfs tanks and acclimatised to completely new tank etc).