TBL and PBL (2)
Task-based learning and Project-based learning

So, to cope with the Fishbone activity students work in groups.

To me the ideal variant is a group/team of 3 students: 2 are too few for collective thinking, 4 are a bit too many and besides students tend to work in pairs within the group of 4 and then just sum up their results so there is no real discussion.
Of course the way you organize it depends on how large your class is.

The same important is the changeability of a group  as it will be tedious if the same students work in one and the same group the whole year round.
The first time make this process comfortable for them, let them make groups on their own, then you can do it yourself knowing students' level and preferences.

The same well you can try it when there are students of the same language level in a group and when their levels are different.

Sometimes when the students are very close friends and very emotional persons at that, their working in one team can result in a very noisy atmosphere and a little bit of a chaos about the way they are working and interfering with the others'.
So, psychology matters!

YOU FEEDBACK IS ALWAYS WELCOME!!