Hi! I've been wanting to keep a pleco or an algae eater for a very long time, however, I was already busy enough with my existing fish and didn't want to add any other fish to my collection, but recently especially over the summer in my pond, there was so much algae and there were days where I could barely see my fish. I did some research and according to most sources, adding a pleco or an algae eater was the solution. I was planning on getting some plecos, but it turns out there's more than one species of them. I was wondering what type of pleco and how many I could put in my 3000 G pond(Koi+Goldfish)(it gets as low as -20 where I live), and in my 120G(Common Goldfish/Tiny Koi), 55G(Large Fancy Goldfish) and possibly my new cichlid tank that I'm almost done cycling(75 G) as well as my small fancy goldfish tank(37 G), and my molly + betta tank (29 G).