The less bottom dwellers the better IMO. All h-e-double toothpicks will break lose when the pair of kribs have a group of fry and they will unleash their demonic wrath on anything that comes close to the bottom in the area where their babies are
. Even fingers...my male ninja-style pecked on my finger when I was replacing a plant that floated to the top.
Just make sure to have plenty of caves and hiding places. My cories got beat up pretty bad by my krib parents in my 55 gallon when I had it as a FW tank (it's brackish now).
But - there is nothing cooler than experiencing krib parent behavior. I'm now in my third generation of babies and now the mom of one batch is flirting with one of her sons from her last batch!
She wants to breed with her son! Heh heh heh.