Check out Underwater World Low-poly 3D model on CGTrader for $79. High-quality mesh by ithappy: 280000 polys, 265000 vertices. Rigged, Animated, PBR.
UNITYPACKAGE (Unity 3D, filesize: 59.3 MB), BLEND (Blender, filesize: 303 MB), OBJ (OBJ, filesize: 335 MB), FBX (Autodesk FBX, filesize: 121 MB), MAX (Autodesk 3ds Max, filesize: 475 MB), C4D (Cinema 4D, filesize: 204 MB), MA (Autodesk Maya, filesize: 534 MB), GLTF (glTF, filesize: 251 MB), UASSET (UnrealEngine, filesize: 273 MB), STL (Stereolithography, filesize: 167 MB), JPG (JPG, filesize: 53 MB), TEXTURES (Textures, filesize: 8.38 MB), UNITYPACKAGE (Unity 3D, filesize: 59.3 MB)