Ridgetop
Herd Master
We did that with the 100 gallon horse troughs. DH would wonder why his goldfish kept disappearing. One day he was admiring a couple large white birds by the troughs and asked what kind they were. I started laughing and told him it was an egret. After that he would run outside to scare them off whenever they appeared. LOLget bigger ones (the long metal ones that hold like 100 gallons or something) and let them get some algae and put a few feeder goldfish in them... they will eat the mosquito larvae, work on some of the algae... and many even will breed and give you tons of little goldfish...