I'm unable to decrease the number of triangles of a mesh

[builderstafsa]

Hi, I want to put that mesh file on my game but it gives me an error because of the number of triangles of the mesh.I tried to decrease them on different sites but I couldn’t do it.Can anyone help me do it?By the way, it’s made by an ai so I’m unable to edit it on blender.Here’s the file if it’s needed:
A_realistic_floating_0108193032_texture_obj.zip (2.9 MB)

[builderstafsa]

And I got that when I decreased the number of triangles:

The original one looks like that:

[slav4335 (slav)]

if it’s an obj, you can edit it on blender. i don’t see your issue with that part

[Scottifly]

How many triangles are in the original mesh?

Can you get the AI to create it again with less tris?

Are you using the DoubleSided property?

[awry_y (johnny)]

untitled.blend (1.6 MB)
Try this new file.