Overstocked fish tank with way too many Blood Parrot Cichlid

I just came across this restaurant with a large tank full of Blood Parrot Cichlids, and a few common Pleco. I was amazed by how crowded their fish tank is. There are too many fish in there, they almost can't move around without hitting another fish.


I took a few photos of their fish tank full of Blood Parrot.








Judged by the fact there are three filters in this tank, one power filter, two sponge filters, whoever set up this tank obviously know about fish. I do not understand why he or she would overstock a fish tank like that while he/she is no newbie fish keeper. It would be hard to keep the ammonia down in an overcrowded fish tank even with 3 filters.

P.S.
For the people who don't know. Blood Parrot or Red Parrot is a unnatural fish species, a cross between several different cichlid fish species.