I would have thought a lot of the dwarf species would do ok with the knives, perhaps not with birchirs though.
Most jewels get too aggressive. The only other bigger species I have kept have been buttikoferi,far too big and aggressive. The other large peaceful African I have kept was oreachromis mossambicus(may be spelt wrong from memory)
I found the Mozambique mouth brooder very peaceful but gets far too large for a 4 foot.
There are smaller species from this genus that may work.
Most jewels get too aggressive. The only other bigger species I have kept have been buttikoferi,far too big and aggressive. The other large peaceful African I have kept was oreachromis mossambicus(may be spelt wrong from memory)
I found the Mozambique mouth brooder very peaceful but gets far too large for a 4 foot.
There are smaller species from this genus that may work.