Fight takes place here:
In a deep coral archipelago in Corellia's oceans. There are stone columns spread around within about 10 meters to each other, spread 90 meters wide. There is a large overhead dome connecting the columns with several holes spread throughout. Count Dooku is upset because Kit Fisto stole his cheezits. He's not bloodlusted over it. He just wants them back.
The water is suited for Kit Fisto. It's slightly on the cool side. He's wearing pants.
Dooku has a partial SCUBA suit and a limitless supply of oxygen. No jet repulsors. Dooku is not suited for the water. He's not wearing pants.
Both have lightsabers. They are surrounded by several dozen worrmps:
They look like they can breathe underwater, or at least I hope they can.