@Mr Gharial here in Australia, native fish displays (both freshwater and marine) are fairly common at aquariums, a few aquarium here keep only native species! I suspect this is mainly due to the difficulty of obtaining exotic species due to strict import laws. As for private aquariums, natives are often almost completely forgotten!
I'd love to keep some more native species! I have my eyes on Pacific Blue-Eyes, they're common in the wild here, although they are a little tricky to catch! I'd have to get rid of my Neon Tetras first though - I tried keeping some blue-eyes, only for my tetras to nip their fins to shreds! I'd never heard of neons being fin nippers, I thought they'd get on with blue-eyes swimmingly!
I think it's partially also because Australia is very proud of it's native fauna, most Australian and N/Z zoos will display a majority of marsupials and native birds. While European zoos will mostly display Asian and African animals, because they consider their local animals "boring".
Why show a European lynx when Asia has much bigger and "more interesting" cats. Why show a fallow deer when Africa has a plethora of "more interesting" gazelles. Why show a wild boar when etc. Australia's fauna is unique, so it can't be replaced by a "better" species.
