PlanetCatfish.com

a 90 gallon 3' x 2' x 2' tank? I am open to all predatory catfish suggestions, common or rare, but just something reasonably priced.

Here's a beauty you can get for free if you live in the Western US:
http://www.planetcatfish.com/catelog/sp ... cies_id=32

All you need is a fishing pole and some chicken gizzards.

If you want to keep bullheads find a slough in late Spring, just off the main flow of the ajacent river and it is easy to collect one inch fry. Usually they occur as a tightly packed black ball with the male standing guard nearby. You can collect hundreds with a dip of the net. Just keep a few and watch them grow(fast!) I have done this many times, especially as a kid.
The Sorubrim lima, shovelnose Cat, is more exotic and I think more interesting fish and doesn't cost much, $15 and up, depending on size.
There are so many possibilities to choose from.
I live just a few hundred miles west of Montana at the confluence of the Clearwater and Snake Rivers, major tributaries of the Columbia River.

limas definatly a good choice, a very sociable cat best kept in a pair atleast, i have two and there really fun to watch and highly inteligant.

Can I keep a Sorubim Lima shovelnose catfish in my 90g (3x2x2) for life?

Yes, I think a 3 x 2 x 2 tank would be about right for a group of Sorubim lima - the cat-eLog lists 420 mm, which may be a little bit too big for a comfortable living in that tank, but most likely they'll be OK.

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Mats