Hello again.
Thank you very much for your help.
I read the article in PCF about L260, and as you said it, the belly diferenciation is not 100% accurate.
I'm saying this because I was alerted that there are several ways to gender your hypancistrus, and the most comum is the hairs in the first pectoral fin, or the hairs (odontes?) near the operculum. And has I know, there's still another way, using the tails. Some say that a male has a sharper/pointy tail-edges. As you can see, that's not agreable with my fishes
Oh well... at least I have a pair (M/F). I believe I can say that... or can't I?
Although at the present time they're in a communitary tank, the one with the white belly roams free in the aquarium, as the other one stays almost the entire day in a cave.
Once again, thank you very much for your help.
My regards.
Luís Fortunato