I was trying to figure out how to catch some of the yet "uncaught" fish. Since the fish in Fishao are fish that exist in real life I thought that google might give me some ideas, and it did!
Here is what I have found so far:
Lionfish (Pinheira Beach):*According to a study that involved the dissection of over 1,400 lionfish stomachs from Bahamian to North Carolinian waters, Pterois (Lionfish) prey mostly on small fish. The amount of prey in lionfish stomachs over the course of the day suggest that lionfish feed most actively from 7:00–11:00 am, with decreased feeding throughout the afternoon.
Nassau Grouper (Pinheira Beach):*It is a solitary fish, feeding in the daytime, mainly on other fish and small crustaceans such as crabs and small lobsters. It spawns in December and January, always around the time of the full moon.
Arapaima (Possibly a fish that exist in Rio Tropical, that Bob is talking about):*The diet of the arapaima consists of fish, crustaceans, even small land animals that walk near the shore./.../ As the water rises the eggs hatch and the offspring have the flood season to prosper, during the months of May to August. Therefore, the yearly spawning is regulated seasonally. (This MIGHT mean they are most active in fishao from May to August)
Good luck out there!
* (Source: http://en.wikipedia.org)