The tank is 4 feet high, a little over 3 feet wide and 8.2 inches long. Has a 180 gallon sump and some solids pumps etc on it.
Photo found below. Hard to take a full pic, tank is too massive to fit in my camera for a good shot. A lot of these guys look small in the photo but they are very large. The size of the tank makes them look tiny.
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Okay yeah, I'd say definitely pass on the pacu. Even if the tank were empty, it still might get a bit cramped for a fully grown pacu.
I'd call that a fully stocked tank.