Cheers Joey.Hi -A taught pond net will do the job with 2 -4 inch clearance from the water or piano wire zig zagged - Gulls - wood pigeons and worst of all Herons { who will empty your pond in five minutes -}
on ebay or Amazon £6.50p
://www.amazon.co.uk/Blagdon-Clearview-Pond-Cover-Net/dp/B002TPTS52/ref=sr_1_2?ie=UTF8&qid=1527006279&sr=8-2&keywords=pond+cover+net
they have to be on tight and have 2-4 inch clearance form the water, you can get Gnomes etc to weigh them down too, which are then an attractive feature - no net no fish if you want to leave a gap in one corner for Frogs that's your choice - ill advised as Frogs Toads will chase your fish to have sex with and stress will kill your fish -
also use a Bio filter works just as well as the expensive light ones!
I have 15-18 young 2 inch baby fish now it's nice to be a Daddy again!
removed two frogs and sealed my pond up with a net no entry next year as the large fish eat the frog spawn anyway
PMD YOU TOO
@Armel problem sorted