extending the top of the tank edges

[clarence]

I am building in a 5' tank in a bathroom where the tub used to be. The ends are close to the the wall. Anything that goes over the ends can't be retrieved or cleaned up. I have about 6 inches clear behind the tank. Does anyone have any experience of raisingthe edges of the sides or back of a tank. I was thinking of sticking a piece of acrylic on the top edges as a means of containing livestock and water at these locations. My tank has a plastic rim. Any Ideas?

Clarence