You are dealing with the facts that lox have bad eyes and a tendency to wander. If you could get them all in the fight at once you could probably get by with less of them.

And ofc this is a game so they don't do the logical thing when something 5 times their size and on fire appears (run!) or the thing we want them to do (attack!) but they continue to derp around the area till they see Yag and judge it is close enough to pose a threat or, much more likely, Yag attacks them. So, like in the video iirc, you end up with 3-4 lox fighting at one time rather than 40. Amusing possibly but not particularly effective.