I make some pretty cool Aquarium  or Tank like effects with the school of fish particle but a find that a lot (all)  of the time when I have the fish coming from the left to the right or in a combination of the two directions , their swimming upside down as apposed to going from right to left. I'm sure there's probably some easy fix but I've tried changing every thing, Of course you have more ribbon settings here. but I've tried changing the direction and emit positions as well. I've been turning the barrel off and using the linear polarization to achieve some more natural visualization. For Example - If you use the Random Direction From Center with the above configuration your notice the fish swimming from left to right are upside down.  ! ( The Center confinement was turned off too ! )