Woops. Sorry, should have read the full post.
The different body shape tetras give a different way of sexing them
eg, the Back Widow, - - take away all the fins,
what shape body do you have.
Round or ovalate??
The round ones are the females.
Look at a group of tetras,neon-shape for example
You will see slim bodies and fatter boddies, fatter =female.
Also the longer shaped tetras like the neons, that have a longitudinal line running the length of their bodies, will be bent (the line that is) if it's a female.
Colour variation of the eyes, eg, congo tetrashave green or blue eyes, green = females.
The head and taillight tetra types are easily sexed by their shape, fat v slim method.
Of course you can't leave out the variations you have with the male V female, where as in most species, the male is more gaudy than the female.
Ever noticed when netting a group of tetra in a fine net, how sometimes you'll get some that snag and just hang suspended in the net??
Those are males, they have hookson their anal fins.
With the emerald eyes, and I think they may be emerald eyed rasbora, just go by the fat/slim method.
But the surest way of sexing them is that the ones that lay eggs are females, and if any babies appeared, you had at least one male in there somewhere. :roll:
Alan 104