Is there anything in particular you like about Pikes? As said above Dwarfs would end up as snacks and I think a lot of the easy to track down Pikes could be too aggressive for the Oscar and SDollars. I believe there is a group of Pikes that get to around 7/8 inches that could work called Saxatillis (spelling) but worth a search for more info.
If you like them because of the snake like appeal what about one of the smaller Bichir species?
Wills