Okay here comes the dumb question...How old do the O's need to be to be able to observe the vent size/shape or are the vents only visible during breeding?
The photo example show an obvious mature pair in the process of spawning. My O's are currently 6-7 inches and have definite differences in behavior and coloration, one very dark Tiger (all of the time) and one chocolate brown Tiger (until it's excited and then it gets darker).
The darker (and smaller) of the 2 seems to be more passive doing alot of side swimming and posturing when the larger is around.
