the main species is Galaxiids i think??
i was in the coromandel a few weeks ago. I snorkled up a few rivers. it was amazing!. the rivers are packed with 2 or 3 kinds of galaxiids(yellow, orange,blue. and they all have mottles like discus! you now they shinny lines, =p) thier about 10cms long. Theres mostly just rocks and bog wood on the bottom.
about 20 foot down there were fish about 15-25cm big they were in a cave.
there were baby eels too.
oh yeah and there were some fish that schooled about 3 foot from the surface they looked a bit like rainbows.
and the fish on the bottom (the main ones) had there eggs stored on the foreheads!!
it looked so wierd. i thought they layed them under stones.
the fish look a tinny bit like the salt water triple fins that we have in nz.
im lookin at doing native freshwater and saltwater tanks =\
i dont think youll need a heater. but good water flow. with good water flow
the stream i think was called Little Anne.