Help with tetras

[maestromad]

Hey guys. Recently acquired 5 red phantom tetras. I am trying to sex them but having no luck online as everything relates to black phantoms so the pics not great.
Also two of them have got a white mark in what I would call the saddle back. It's not fuzzy or raised just a discolouration I noticed this yesterday. I've tried to take a pic but these fish are very camera shy.
Any help would be great!

 

[librarygirl]

Males have leaner bodies than females. But the best way to distinguish between sexes is their dorsal fins. The male dorsal fin is longer and more sharply pointed than the females. Male fins are generally solid red. Female fins typically have a dark spot with a white tip.

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The white fuzzy patch could be an injury, just keep the water clean and watch it. It could also be the startings of something more sinister (e.g. columnaris or a fungal infection) so keep an eye on it. If it changes color or consistency or starts to spread or the fish are showing signs of distress it may need to be treated.

 

[maestromad]

Thanks for that! From going by the white spot I possibly have 3 females and 2 males i may well have to invest in some tank decor that protects eggs I think!
As for the white mark. It's not fuzzy I think they may have injured themselves on something one did it the first day I got them when it got stuck behind the filter silly fish