Help Background disappear into my scene update

[Prosper75]

Hello, I would want to make a movie under the sea, with a background with bubbles as this link:
https://3dwarehouse.sketchup.com/model/1b9af050281de59e967bf54a1f364120/Golden-butterfly-fish

I would want that the image of bubbles remains fixed exactly as this model.
But when I do scene and when I update scene, the bottom with bubble disapear...

How I can make so that this bottom with bubble remains fixed in front of the camera throughout my scenes and travel of camera?

Thank you for your help!!!
Hello, I would want to make a movie under the sea, with a background with bubbles as this link:
https://3dwarehouse.sketchup.com/model/1b9af050281de59e967bf54a1f364120/Golden-butterfly-fish

I would want that the image of bubbles remains fixed exactly as this model.
But when I do scene and when I update scene, the bottom with bubble disapear...

How I can make so that this bottom with bubble remains fixed in front of the camera throughout my scenes and travel of camera?

Thank you for your help!!!
look at my image:
http://i64.tinypic.com/zuk01f.jpg

[filibis]

I'm not sure what you're doing wrong but here is some gifs that might help you. Also check this: Creating Scenes

That's a watermark image (overlayed).