Just got into a home that has an impressive backyard. Complete with a good sized pond. It has a waterfall & a dozen or so large fish. I'm fairly certain they're Koi of some type. Most are about 2 feet long. It has plants a filtration system along with some sort of ultra violet light thing. I really don't know anything other than to feed them a couple times a day & clean the skimmer weekly. I've stumbled onto this site in search of support. Once I figure out a few things like how to put pictures on here I'll have lots of questions. Oh by the way I'm in southern California.