55gal is gonna limit the pikes you can get. Unless you have a larger tank, say 125...then you can get some of the 'funner' larger pikes! The pike will become one of the dominate fish in the tank, lol. The mota will have a run for its money. It shouldn't be too bad though. I had mine with clown loaches, just make sure the clown loaches are OVER half the size of the pike. Crenicichla sveni would be a good pike fer yaz! Or some of the dwarfs!
Crenicichla sp. 'xingu I' eh? Just so yaz know, they don't look anything like what they do as juv. when they are adults. Also, sp. 'xingu I' are some of the more aggressive of pikes...which can really be a bugga. I would try Crenicichla acutirostris...they are more laid back and look awesome as juv. and as adults. Don't get me wrong though, sp. 'xingu I' are great pikes...just gotta be aware what cha are gettin into. Most peeps don't realize what the turn into...lol...heres some pictures of acutirostris...