um i am trying to keep my snakehead with other monster fishes so if 150 is not enough i would still be able to upgrade to another 170 gallon
btw my current fishes are oscar and bichir
there are (as I'm sure you know) many different types of snakehead.. if you were to answer or even better send a picture of your snakehead or the snakehead you intend to buy we could better help you!