How can you tell the difference between male and female platy?

Answer 1

The female's back fin under where her anus would be (behind the two pectoral fins) will have a fin that is fanned out...The male's fin in that spot is tucked back and you will usually see the gonopodium (penis-like organ) which is just a long straight thing that points backwards. A female with her fin tucked up can look very like a male, but when she relaxes and hovers in the water she will almost always let her fin fan out. It is difficult to sex livebreeders while they are swimming. The male sexual organs are also some of the last characteristics to develop, so juveniles suddenly switching from female to male is normal. It's not wise to buy platies or other livebreeders based on sex until they are fully grown.

Answer 2

A really easy way to find out is by looking at the anal fin. A males anal fin is long and pointed, but a females is rounded and short. Check out these sites: http://web.tiscali.it/acquario2000/imagesplaty.JPG (the top one is male, bottom is female for this site) http://www.fishforums.net/index.php?showtopic=46309 Hope it helps!

Answer 3

Females are plain exept mine and males are fancy. Katniss is a female Betta and I've had her for a few days. She's blue, purple, greenish, and red. And a lil' white. Her fins are short unlike a male's.

Answer 4

If the fish has a long protruding anal fin called a gonopodium then it is male. I think it can retract it, not sure. The female usually has a gravid spot just before the anal fin.