I think in this case it works not because they cant catch the gatf but because of the sheer numbers of tank mates that its in with. Also in this video it looks like the gatf are maybe 6-7" and havnt really got their super aggressive behaviours yet. If it was just an mbu, gatf, and armatus id bet it would be a whole different ball game. You can always try though. It depends mainly on the personality of ur specific fish.

But beside from that... I agree, it has everything to do with the personalities of your specific fish. Having a 'pair' of Mbu's is rare. You should jump on it.
