Standing in the water while electrocuting fish sounds like a bad idea...
It's a bug. I have no idea why it's happening, given the fact that my clicking-on-water code is practically the same as for the bucket...
I've tweaked some of the numbers:
Regular Rod gives 0-6 fish for 10k eu.
Advanced Rod gives 0-8 fish for 10k eu.
I tried to add a delay, but it just locked up the item's usage.
Edit: I might also add config files for these values later.