In a 4ft tank it is very hard to impossible to house a big jaguar cichlid w/ another fish, there is not much room to hide. In about a year the jaguar will get to 10"to 12" and so its aggressive personality (You can try convicts and make sure there is a lot of hiding spaces). However a 6' will be ok, housing other aggressive CA cichlids like texas, jd, gt, convicts.