I have fluid behind my retina, can you tell me the treatment for this?

Depends: I am guessing that you have seen a retinal specialist since they are the most likely ones to diagnose fluid under the retina. Hopefully you are not seeing an optometrist as they cannot deal with a problem like this. Fluid under the retina will alter the vision and lead to possible permanent vision loss. You should seek out a retinal specialist as soon as possible.