It's been a couple of years since I visited. I was slightly disappointed by the aquarium, as the tanks' decorations looked a bit synthetic and I was hoping for some larger tanks - perhaps that's unfair and I ought to visit again soon.
I remember the old aquarium, which was at ground level, very clearly. The design was unusual as most of the tanks were the same size, relatively deep and viewed end-on, giving really interesting opportunities for aquascaping. I particularly remember the shoal of minnows in the native section, a big conger eel in the native marines and then a lovely display of discus and some huge bleeding-heart tetras among the tropicals. I think Gordon McGregor Reid was the supervisor when it was first opened.
Alan