Helene – thank you for your advice. I will leave the female with the other girls for a while. The lonely male seems to be very comfortable without her. I will rearrange the bigger tank in the near future and will then try to catch the little runaway.
I have never experienced one of my paros even trying to jump, too. I think the fact that my quindecim female jumped into the adjacent tank is really exceptional.
As I told you, I have been ill for a longer time. The tanks have been rather unattended for about 6 weeks or more. My husband just fed the fish and filled in water where it had evaporated.
(Short note: the water values stayed still fine in these untended tanks, pH 5,5, conductivity 45 µS)
As soon as I was able to care for the tanks again, I cleaned the panes, made greater water changes and – above all – removed the lush plant cover. Ceratopteris, Riccia and Lomariopsis sprawled all over the surface.
Now the quindecim female loves to hide just in this thick plant covers. I think I frightened her by removing big parts of it. Maybe I even lifted her with a handful of plants and she slipped off into the other tank.
Today I succeeded in taking some baby photos: