[QUOTE=Casey09;4058992]
Hmm.
I have a bunch of goldfish in an outdoor pond. My understanding is that the water has to be moving (to provide oxygen to the fish) in warm weather, and that for the whole process to work, you’ve got to have a lot of plants in there. It does get algae on the sides - the goldfish don’t seem to eat that much of it. The water usually gets pretty clear - but only after the plants are in (and in cold weather). Every spring, it goes through an “algae bloom” and is green until it has a lot of plants in it. They do eat the bugs, though.[/QUOTE]
I have a pond with Koi in it. I’ve always been told that they need moving water as well. So I have to leave either the filter or the waterfall going all the time.
To combat Algae, I’m looking to find a Chinese Hi Fin Banded Shark. It’s not really a shark, but a little fish who has a voracious appetite for Algae. I don’t know how they’d do in a horse water tank.