What would be a good way to rid our drinking water tank of mosquito larvae?

Question

It has a roof, obviously not a very tight fitting one but I'm surprised that the larvae like living in the dark.

Would it be a good idea to suffocate them with a very thin layer of vegetable oil?

Answer 1

The oil would go off...

Powerful UV light should kill them off without affecting the water.

Or keep fish.....

Answer 2

maybe use a silicone sealer and seal the gaps-not sure of what you have

Answer 3

A thin film of parafin is usually recommended. Check  out the Aussie pdf link on water storage below...

Answer 4

Mosquitos do not breed in moving water. If there is a pump that should be sufficient to agitate the water in order to get rid of them. Or you can install a device to aerate the water.

Answer 5

Ginny's answer is very good.