I have watched that thing for about a dozen back and forth cycles. The fish movements didn't repeat in that time. I am about 87.3% sure the flora changes. I am about 46.8% sure the length (ie distance) of the cycle changes. I think it would be cool if it were based on the hours of daylight for the IP address location.
I am 99.8% sure I just saw a fish I'd never seen. It's kind of like a koy except the front 1/2 is purple. I wander if it is possible to introduce AI generated fish and flore.