If you wouldn't be terribly upset about it if the odoe did go nuts on him, I'd chance him in the 180. Who knows, I've heard about some fairly aggressive scombs, at least they are fast swimmers to my knowledge. He should be able to avoid the odoe, but it's definitely not a 100% given. They are cool, and if you've always wanted one, $60 isn't a steep entry price. I personally wouldn't chance him with the ATF yet, not until the ATF was a lot bigger (they just don't have any mass to them at that size, so I'm pretty certain a scomb could eat one without struggling too bad). It's your call, but I'd probably do it (you obviously know your odoe and other fish much better than I do, though).