It looks like Fluent exported the geometry of the mesh. Try putting a sketch on one of the triangular faces. If you can, then you have the equivalent of an STL body, with thousands of flat faced triangles instead of a nice smooth surface. If you want a nice smooth body, you will have to build it yourself, trying to match the shape as best as you can.
PS. Isn't there any way to do the whole round trip inside of ANSYS?
Thank you for your answer! I have actually converted the STL mesh to an IGES solid body but, just as you said, it hase thousands of surfaces which causes ansys to crash when I try to do anything with it. The only way inside ANSYS would be a 2 way FSI taking about 1 week of computation time on my computer. Not the best expectation!
I am currently figuring out how to solve this with mesh based programs like TGrid, ICEM or Gambit. However, I have not found a solution so far.