Other than the fish prices affecting how fast they are sold, how do the other factors affect sales?
Advertising and decorations draws in more people, but does that increase prices too?
What about over saturation of a species? If you try selling too much of one breed, do they stop buying? I noticed that a few times, selling about 10 of a single breed at one time. At first they go really fast, slow down about half way, and when there's only 1 or 2 left, I sometimes even have to lower the price before anyone buys them.

And I think this is more of a bug, but the other day, people were not buying anything. I have 2 games running at the same time, and no sales on either of them. I kept lowering prices to the point people's balloons showed the green dollar sign with a smily face, so I know they are happy with the prices, but still not one sale. It wasn't until I quit out of the program and restarted it did people start buying again.