Stephen,
A 55g tank will be fine for rainbows. I understood Dianne to say that she was
considering purchasing a 55g tank and I was trying to point out that if you are
going to buy a tank and you have the room for a 55 that a 75 would be better
and it takes up roughly the same amount of floor space. If you already have a
55 then it will be fine for rainbows.
As far as tank set ups, I am trying to simulate an Australian river or stream.
Having never seen one in person this is proving to be difficult, but based on
what I've learned here is my plan.
I am going to use natural to light colored gravel that is fine to medium
sized. I plan to have the tank well planted with plants that my bottom feeders
won't eat. I would like to have some type of wood that simulates a fallen
branch because I have seen this in several pictures and I think it might look
good :-). I also would like to put some rocks on the bottom because rivers and
streams sometimes have rocks.
This is what I'm thinking about doing. I am open to ideas especially from the
"Big Guns" that live in OZ and have seen these fish in their natural
environment. I realized that streams and rivers probably differ from place to
place, but I am trying to find the "happy" medium :-)
John