How big a tank

[Gix]

Howdy folks,
I want to evntually set up a tank and put in a little of all of my favorite unique fish. The list goes as follows:
1 African Brown Knife
3 Clown Loach
1 Ropefish
1 Pictus Catfish
1 African Butterfly

How big of a tank would i need to keep those all together? I really just need a bare minimum estimate. I'll try to get one as big as I can so I can toy around with it (maybe add more pictus), but I want to know what the smallest possible healthy aquarium size is. I think all of these do well in a 50g, but I don't know if there's enough room for all of them...
Any help is appreciated! thanks!

 

[Elite]

I'd say at least a 150...clown knifes get HUGE. even a 150 may be small for them. I wouldn't put an african butterfly in a tank that size, though...they like shallow water. Maybe other people have other ideas?

 

[Gix]

I chose the African brown knife because, unlike its cousins the clown and black ghost knifefish, it doesn't get huge. It'll max out around 8 inches.

 

[Elite]

Oh, sorry, somehow I thought you'd said clown, lol. Anyways, I'd say 100 gal, now, possibly as low as 75.