Hello all...here's some info regarding the Annapolis Mall tanks. I happen to know first hand!
Geoff Mellgren from Amazon Creations has the maintenance contract for the tanks. On the install/taping the second tank had not been completed or delivered so they had to do that install a few days later, after most of the crew was gone. That's why it didn't get in the show.
So far as the stocking goes...they intentionally overstock the tanks for the unveiling and filming. So yes, there are fewer fish now but not necessarily due to poor maintenance. The system as it was explained to me was a bit quirky and had some interesting obstacles to overcome. As mentioned before, one of these was the natural sunlight from directly above the tank-- an ongoing issue. The mall was on board to tint or black out the sunlight at the install but not sure what happened.