We all know how difficult it is to identify the sex of these fish, so please post a picture in here and we'll try to help you (or at least give an educated guess!).
Go to Gallery, then click on Your Personal Gallery below the Hall of Fame album. Then click on Upload Pic to download your pictures from your hard-drive to the site's gallery. Then simply link the pictures from your gallery to the Sexing Forum. To do this, right click on the picture you uploaded, click on properties, highlight the URL. Then copy it and paste into your message and add then highlight it again, click on the Img button above to successfully post an image!
Example, it won't work but just to show you how it should look like.