It can get even hotter in my house than outdoors sometimes, I cant leave the aircon on all the time either. Not really Aussie native, but live here, Brown Trout.
Its temp, it will do him a while till I dig up the veggie patch, then it will be approx 12ft x 6ft x 4ft. the stream I got hiim from wasn't too deep anyway, so he has some room to swim at the moment.