You guys have done pretty good already...lol...pretty soon I won't even have to answer...haha. Lugubris, Reticulatus, and Acutirostris group pikes are pretty much out bro. They all easily get 12"...some quite a bit larger. It would just be sad to see one cramped into anything smaller than a 75...and even then it would be best if it was a solo fish. Saxatilis and Wallaci (dwarfs..hehe...) are you best bet. They do have a lotta spunk and are willin to give you a show. They might be bashful at first but give them a few days and they will be the boldest fish in your tank. Garunteed. Few options, as stated, Crenicichla regani, Crenicichla compressiceps, Crenicichla notonatus (bah..sp...), Crenicichla alta, Crenicichla sveni, Crenicichla lepodita. For the last three pikes, you will need to either keep them solo, or keep them in a pair...ALONE..in the tank. For the dwarfs, you can set up a community.