They Have scales.
because they are blue
These are saw toothed scales. One of the fish that has this kind of scale is the American Bass.
No- dolphins are bigger, and bluegills and dolphins do not live in the same place.
Behind that prepositon.
on a blue fish
Yes.
The type of fish that were actually in Hatchet were bluegills, sunfish, and perch.
Bluegills normally spawn in late April in the south, later in the north. June in New York and points north.
On rare occasions, bluegills can reach up to nearly five pounds, but normally average less than one pound.
They eat small insects
No they are not but they may try to chase you away from their nesting area. Bluegills have no teeth, so they cannot break skin if they swim at you with their mouth open.
They are about 3 to 6 inches long.