Vieja synspilus question

[House 64]

I am contemplating picking up a pair of Vieja synspilus but had a couple-few of question.

1.) One of the Vieja has a black underbelly while the other one doesn't. From the side they look the same, just one has black from the bottom jaw to his tail..... can't figure out if that difference is a distinguishment of male and female?
2.) How do you sex them without venting.... I'm sure it's not accurate but gives me an possible idea.
3.) How large/old do they have to be to breed?

Thanks in advance.

 

[balton777]

With Synspilum, I've seen quite a bit of color variation from fish to fish. Especially with some of the blackish markings so it's probably perfectly normal. Males tend to grow larger and often get a nice nuchal hump but tend to be more narrow bodied than females. I've seen breeding start as small as 4". Good luck.