Water Troughs, Mosquito Larvae and Cooking Oil?

[PurpleSpots]

This year the mosquitos appear to be particularly bad, and I keep having to empty the water troughs more frequently than normal to stop the larvae in them reaching maturity which would mean yet more of them being around.

I'm concerned at using water when I might not need to - partly to not be wasteful, but also partly because of the water bill!

All the troughs are automatic, so the water is gently moving already, and making it move more isn't an option. I've done a little googling though, and have seen that adding a thin layer of cooking oil (a few drops) to a water trough is said to be effective against mosquito larvae as it means they can't break the surface of the water to breathe. Has anyone had any experience with this method?

 

[rabatsa]

I suspect any equine with pink skin around the muzzle will get sunburn from oil coating the skin.

 

[ILuvCowparsely]

This year the mosquitos appear to be particularly bad, and I keep having to empty the water troughs more frequently than normal to stop the larvae in them reaching maturity which would mean yet more of them being around.

I'm concerned at using water when I might not need to - partly to not be wasteful, but also partly because of the water bill!

All the troughs are automatic, so the water is gently moving already, and making it move more isn't an option. I've done a little googling though, and have seen that adding a thin layer of cooking oil (a few drops) to a water trough is said to be effective against mosquito larvae as it means they can't break the surface of the water to breathe. Has anyone had any experience with this method?

In the past we always had a couple goldfish in the tank to eat them. They do need a sheltered area to hide

 

[Highmileagecob]

You can skim them off with a kitchen sieve, but we gave up after a while. The swallows/swifts in the stables do a good job of catching them though!

 

[poiuytrewq]

In the past we always had a couple goldfish in the tank to eat them. They do need a sheltered area to hide

Don't you find the goldfish poo more troublesome than the bugs? Goldfish are very dirty fish. I think I'd rather my horses drink the larvae than fish gunk.

 

[Glitter's fun]

I've done a little googling though, and have seen that adding a thin layer of cooking oil (a few drops) to a water trough is said to be effective against mosquito larvae as it means they can't break the surface of the water to breathe. Has anyone had any experience with this method?

I do something similar in the water butt in the polytunnel. I put literally one drop of washing up liquid in it to disrupt the surface tension. The larvae all sink & drown.
It's not moving water though, so not sure how that would work.