[feldon34]

Let's say each fish has a "preferred" vector or direction it wants to go. That vector is extrapolated about 3 inches ahead of each fish. If that vector crosses any other fish, then both fish need to be "steered" slightly off the vector line. If you are starting to steer around another fish with fully 3 inches to go, it's unlikely they'll conflict.

Also, by having spheres figure your avoidance, you're not taking advantage of the shape of each fish, which is larger in the front, smaller in the back, and each fish is mostly flat so several fish can slip past each other in a confined space if they are side-by-side. I think calculus will be required, or at least 3D geometry/trigonometry.

For 9 years, we've been hearing that outside help cannot be trusted to maintain the quality. I'm sorry that Jim has had so many bad business partners in the past (including Prolific), but there are people out there who probably would do a fantastic job helping on this issue. But maybe it will take another 9 years before help is sought. Game engines are getting so advanced now that things like hair, cloth, collisions, etc. are all "free" and just part of the engine.