I sent this to Jim back in 2002, for fish behavioural / interaction ideas...
If you are interested download from this link,
http://www.shef.ac.uk/uni/academic/N.../aquarium.html
(You may (like me) have to run it in compatibility mode if you are on XP or Vista).
Not pretty, but when we do get to see the new fish in MA3 hopefully some new, more realistic, rock picking, chasing, etc etc behaviours will be programmed in along this line...