Hi all, I have 9 platys in a 5 week old 33g tank. They got white spot early on which I successfully treated (only the first two I started with, didn't add 9 in one go). I requested only females so I didn't have problems with numbers and just assumed a couple of them were pregnant but as I've learnt more (I'm very new to this) I've actually got a mix of boys and girls and the ones I thought were pregnant are indeed boys. Is it normally for boys to be bloated like this? I'm not sure it's dropsy because their bodies are smooth. I've included a picture of one of them but they're too quick for me to get pictures of the others!
He's definitely a boy. Sexing livebearers is very straightforward. Females have an anal fin, but in males, this is instead a rod-like organ they use for reproduction (the gonopodium). This pic shows the difference: