Just wanted to let you know:

a). I've been playing on Easy
b). It's about halfway through level three of advertising
c). I just sold off a bunch of the first four magic fish (don't have any other types)
d). I now have $8792 (in case hitting $10,000 makes a difference)

Edited to add:

a). 3/4 way to completing level three
b). Sold more fish and now have $9540