Using gravel as a "relative-size" measure isn't a particularly useful method. If those bits of gravel are fist-sized, then the fish would be quite bit, but if the pieces of gravel are almost sand, the fish is only half an inch long. THere's no way to tell that from the picture.
I somehow suspect that it's fairly coarse gravel (6-8 mm), and that the fish is around 4" (100mm) long. I'd call it a male with those cheek odontodes, but I reserve judgement until I get confirmation that it's the size I guess it is...
I couldn't find any breeding reports on this site, aside from a failed spawn in a post by Janne. That was over a year ago, so it may be that Janne has had more success by now.
They are mature from around 8 cm and males get huge odontodes on the cheek and pectoral fins that the female lacks almost completely. I have not succeeded yet with them to spawn but they show interest at a low pH around 6.0 and very soft water.