If you don't have the tank to keep an animal through maturity, and don't have a plan to do so, it seems awfully irresponsible to keep one. If I told you that I wanted a St. Bernard puppy because he was cute/cool/etc., but lived in a studio apartment with no yard, then even though he'd be totally happy until he was full grown, without a plan to deal with him then, it would be irresponsible of me to get him. Seems like that's exactly where you're going with this bass thing, unless you have access to a 400 gallon aquarium, you simply don't have the environment to responsibly provide him what he needs, releasing isn't an option, and eating isn't either. If there was some legitimate research (and defining "legitimate" is tough) being conducted on the animal, I could understand it, but keeping it for your own amusement until it becomes inconvenient, or dies due to malnutrition, poor substitute for a natural environment, not enough space, etc is wrong.