If they were both males shouldn't they normally fight each other?
As my friend told me, the usually stay close and share the same hiding places in the tank.
Have these fish ever bred in aquarium?
Staying together is an indication that they are male and female, yes.
I'm not sure if L002 has been bred, but several of the small Panaque species have been bred. There are a couple of breeding reports in "Shane's world". It is fairly safe to assume that they all breed in very similar ways.
Really thank you for the answers MatsP.
What is the minimum aquarium that someone can use in order to breed a small panaque (such as panaque maccus ,panaque L'002 etc)?
Do you think that is better to have the catfish alone or with dithers?