43 fish nicely done!! I'm totally with you on the randomization repeating being annoying, it's on my list of things to tweak. I really like the idea of giving the larger fish more "weight" which would balance out the low spanning number as well as their slow speed.
I did notice when I played it in chrome with a bunch of other tabs open it ran extremely slow, but it's not consistent so I'm not entirely sure what's causing it. I'll try looking into it though, thanks for the feedback.