I suppose when young, cutteri and sajica would work, although when I kept both those 2 species, the males became way to massive to really fit that size tank.
I consider a 40 gal only large enough for 4" fish as adults.
My male cutteri easily hit 7", and the sajica about the same, and along with that length, they both had height and girth to match. I also believe the smaller size of females in such a small tank would put them at a serious disadvantage.
cutteri male
[/URL[URL=http://s70.photobucket.com/user/dstuer/media/cutteri/sumerfest09029.jpg.html]
sajica male

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I consider a 40 gal only large enough for 4" fish as adults.
My male cutteri easily hit 7", and the sajica about the same, and along with that length, they both had height and girth to match. I also believe the smaller size of females in such a small tank would put them at a serious disadvantage.
cutteri male
[/URL[URL=http://s70.photobucket.com/user/dstuer/media/cutteri/sumerfest09029.jpg.html]
sajica male

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