That is hilarious!!! I feel your pain.
I have a full grown synspilum and boucourti that never stop eating.
then i added a 30 inch chile arowana and he won`t let anybody eat until he is full which is never!! LOL
I also have some night time fish like you, L-25 and others so I feed them at night but unless it`s totally dark the arowana either smells the food or sees it, so now I feed the plecos at night with a pipe,
I put the food into the pipe and let it reach the crevasses where the plecos are and the arowana can`t reach, the other cichlids are still sleeping and it`s a pain but it works.
have fun!!