Boy -vs- Girl ID in Silver Dollar

[andyroo]

Q: in "typical" SDs, does the male have the clean, flat silver & red anal fin or does the female?
Sorry, I've no energy to look up the species just now...

I'm sitting here watching the thunder & thinking about packing-up to leave office for the day, & watching what looks like pairing (spawning?) behaviour. In both pairs, the one with the mid-body spot & no red is the notable aggressor.
The third silver-with-red is looking a little 5th wheel...

 

[FJB]

Short answer - Female has "the clean, flat silver & red anal fin".
The male has more of a bi-lobed anal fin.

Not true of red-hooks, where the female is the only with the long red hook.

Longer answer - There is no "typical SD's" . In the lesser SD's (Metynnis), there are ~ 16 species, 4-5 frequently seen in the hobby. And then there are 2-3 other genera, with various species, which are seen as well.

 

[andyroo]

I appreciate that the "typical" was being a little ignorant - apologies. I can look up and/or send pics, but I think you've answered my question already. One of these males started with a distinct pointed red fin (IE: fem) but changed - I discussed in a previous thread.

I'd love to get a spawn out of them, but between the RBS, ABK, MTS & others, I'd not expect success. This is part of why I'm quietly letting the bottom get "cluttered" with bamboo & moss & almond leaves in various states of decay. Doing/allowing same in the tank with the zamora cats, which is otherwise swordtails & snails feeder-breeder.

 

[FJB]

Cool !
Do post pictures if you can. Nice to see other's fish.
Good luck with the breeding.