A. sp. Breitbinden - male or female?

[boofeng]

Hello

Below are photos of a single fish, the supposed "female" of a pair passed to me by a friend. The fish came in a Colombia import and were sold as A. sp. Breitbinden.

From the photos, is it possible to positively ID the sex of the fish?

Thanks!

 

[Mike Wise]

I'm not sure based just on the photos. I'd expect much darker anterior ventral fin spines if it was a female. Size?

 

[boofeng]

I'm not sure based just on the photos. I'd expect much darker anterior ventral fin spines if it was a female. Size?

Thanks, Mike!

The fish is at least 3 cm standard length, probably 3+ cm (that's above an inch, maybe around one and a half inches). It should be pretty mature, the import was a while back (about January or February), and they came in reasonably large and well-developed already.

The middle dorsal fin spines seem be serrated (in one photo you can see little ridges along the folded dorsal fin?) - can this be positive ID of a male? (As in, would females only show serration on the first three to four spines?)

 

[Mike Wise]

Still not fully developed. Most brevis-group species don't fully develop their finnage and colors until they are at least 5cm/2" SL (unless stunted). It's probably a young male, but can't be 100% sure. It might not even be A. piaroa (or Breitbinden). We see A. megaptera (or Breitbinden-Kurzlappen) more commonly available now.

 

[boofeng]

Yea, I'm getting used to this, I think! I'll just see how things develop. Thank you!

(You're probably right too about them being A. megaptera, the male fish in this batch all show longer anterior than middle dorsal spines, I'm attaching a photo of another fish from the same import - not mine.)