Looks like a male Crenicichla sp. 'bellycrawler'. Can't see the dorsal straight on to see if there are any spots in it, but pretty sure its male. They are from the Reticulatus group of pikes, which are characterized by their atrophied swimbladder...thus their awkward swimmin and sittin on their belly a lot. They come from fast flowing rivers, thus the low profile and swimbladder. Grow kinda large...my male was 8" before he died..but I've heard they can get up to about 10". Great pikes with lots of personality. Pikes aren't really fond of other pikes...so if you do want more...get about three or four of them since they are cheap and pretty common. Grow them up together and let them pair up...then remove the others. Females will have a black spot in the dorsal....