I have a small backyard pond 4x6 that has two koi , one shubunkin and some guppys and convicts in it. I put the guppys and convicts in there to combat the mosquito problem I had and they were very effective. The problem I have now is that they do what guppys and cons do and are breeding like crazy. I was wondering if there was any small predator that I could put in there that would help control the guppy and con population without messing with the koi. It would also have to survive central florida winters. Would appreciate any input, thanks.