I male krib should work in your tank, but every krib is different and you will need to watach him for the first week.
I highly do not suggest you put a female/male pair in your tank. The female is the one you need to watch. I had a pair that was not even spawning and was fine for the first couple of weeks and then lost it afterwards.
She went after everyone. She attacked my pleco's and cories to the point of tearing fins and I had them in a 45 gallon tank too.
Whatever you decide, please keep an eye on them for the first 2 weeks to make sure.