kribs or butterflys?

[stl2pab]

I have a 55 with an african knife and a polypterus senegalus, and I went to get a pair of kribs today, but they only had 3 left and they all looked like males, so I decided to pass. they did have a ton of anomalochromis tomasi, but they were only 2 inches long and I've read you can't sex them easily. Which species would you recommend. I really want to get a pair breeding in this tank even if the eggs/young will probably get eaten.
Also, I've ruled out red jewel cichlids because I'm afraid they'll kill my knife and bichir. Am I being unfair? Here's a picture. The butterflyfish decided to jump out last time I left town

 

[darth pike]

I really like my african rams. They are hard to sex, I purchased 4 ... two of the largest/most colorful in the tank, two of the smallest. Once home it appeared I had 3 males and 1 female based on finnage and color, but it turns out it was indeed two males and two females, as the smallest 'male' has paired with the largest.

Despite being small, they are active, fiesty fish ... much more so than the larger kribs. Fully colored up they look like mini-elongatus jewels. Even though they are an inch smaller than the kribs, their body is taller so shouldn't end up a meal for the knife.

 

[Will Hayward]

Put some rocks in there and add in some Buffalo Head Cichlids. Just a thought.

 

[stl2pab]

Found some kribs on sale and bought 2. Looks like they might both be female, but I've got a store credit at the place that seemed to only have males last week. Anyway, I got em floating now and the knife looks way too interested. I'll post some pics later.

 

[stl2pab]

Here's the pics. After I got 'em outta the bag they do look like a pair. They've been pallin around together and chasin the poly away from their cave. I think they're gonna do fine in this tank.