I don't beleive the tank size is a problem. I also don't believe the feulleborni will cross breed with the lombardoi.
How big is the lombardoi? The males change to a yellow colour at around 2,5-3 inches. Could be that yours is a male that hasn't matured yet!
I have 2 3ft tanks that have plenty of rocks in them and jave around 30 fish in each, all being wild caughts. Very little aggression shown. Odd bit of chasing around. Had a beaut feulleborni male but lost him when we had a power failure
and I arrived home a little too late and then had to try a source a battery operated air pump. Now have plenty of them with fully charged re-chargeable batteries that last for about 13hrs. This guy was not at all aggressive. My Zebra gold is the most aggressive in this tank.
My pennies worth regarding your problem.

How big is the lombardoi? The males change to a yellow colour at around 2,5-3 inches. Could be that yours is a male that hasn't matured yet! I have 2 3ft tanks that have plenty of rocks in them and jave around 30 fish in each, all being wild caughts. Very little aggression shown. Odd bit of chasing around. Had a beaut feulleborni male but lost him when we had a power failure
and I arrived home a little too late and then had to try a source a battery operated air pump. Now have plenty of them with fully charged re-chargeable batteries that last for about 13hrs. This guy was not at all aggressive. My Zebra gold is the most aggressive in this tank.My pennies worth regarding your problem.



