dude a jag or dovii will shred any oscar alive if the are of equal size. oscars just arent mean. they may not back down but they are not aggressive compared to either of the 2 mentioned. as far as trimacs or midas cichlids go, both can get huge as well. i saw some midas at steinhart aquarium sn francisco that were easily 16 to 18" MONSTERS. these fish would have little trouble defending themselves if the layout of their environment was right. inside the confines of an aquarium, theres not much room for a 3 to 4 foot fish. get you some huge cichlids and make some smaller caves for the channa. as the channa grows he will more than likely recognize his tankmates as too large or to aggressive to waste his energy on. rumble it sounds to me as though you are just looking to see a fight. you will need to have a place for one fish or the other to hide where it cant be reached. a bare tank with an aggressive Channa is not gonna work. you need a larger aquascaped tank if he is that agressive.