When the tank fills it always gurgles. What can be done to fix this?

when the tank fills it always gurgles. what can be done to fix this? And I bet you run out of hot water in a hurry also.
Sounds like the dip tube has fallen down ands the cold water entering the tank is what you hear. This can happen when too much heat applied to the coold water inlet. The dip tube's made of plastic and sets just under the cold water inlet on a plastic flange. When replacing do not apply heat to the area. Instaad, come out of the opening with a 3/4" brass nipple. PS. Do you have heat trap nipples,(see image) already installed on the inlets?
Good luck and thank you for rating my answer, Tom

Thanks speedball1 for the response. I don't run out of hot water however. I failed to state that I have a gas fired heater, your suggested fix would be the same? It just seems to struggle to fill up after use and was hoping the solution would have been simpler.

Do you have a cut off valve on the cold water line above the water heater?

I have seen the washer come off the valve and partially block the entrance of water into the heater. What happens is that as you open the hot water at a faucet it lowers the pressure into the heater to a small degree. After you close the hot water at the faucet the cold water will sound for a few seconds until the pressure in the water heater equals the city pressure or your well pressure, which ever one you use.

I like Letmetellus answer, ( wish I'd have thought of it myself) I think he's on to something. Shut the water off to the house and open up the valve and check bit out. Let me know the results. Regards, Tom

Awesome guys thanks,
I can turn off the water entering the tank and will check out the valve to see if there are any obstructions. I will get back to you with the results. I really appreciate the support. This is a great site. Thank you.
Rick