(Help) Need some help with colliders and Assets.(Images attached)

I have a 3d Model made in blender, and have it imported to unity. The idea is that the model is a artery network and I want the character to be able to swim through it. However with the colliders on the character gets stopped only from the outside, once inside the character is able to exit out of the mesh. I also have a problem with the mesh looking transparent where I can see the sky from the inside and solid from the outside.

Outside is solid

Inside- transparent and character flies straight out

Scene Bottom

Answer found, It was just that colliders set only on outside, After solidifying and thickening the model, it works