What kind of horses? A Koralia nanno might work, but would need to be placed at the bottom of the tank, you'll need to attach an extension cord. Definatelt not an airstone!!!!! no tiny bubbles!!!!! the widespread belief is that if the horses are hungry they might eat the bubbles thinking that it's food, and since they can't pass gas, they'll end up floating. (for this yo'll need diamox) I have 5 ridgid airlines along the back of the tank. I also have the water flow from the return. how much rock work, and how tall? I made this awesome, huge structure in teh tank, the horses loved to swim around it and around it. but it didn't give them enough room to court, so I moved it back. they're happier now. Make sure you leave them room where th ewater returns to the tank, my horses love to go "surfing in the return, sometimes they line up and take turns, 2 of my horses like to hitch onto the tube and sit w/ their faces it the stream (like a dog w/ it's head out the window!) It's hilarous to watch!!!! I also added tree spounges. this is one of their favorite hitching posts! I had to hide it from the light, but they went looking for it. it's ony 10 in long, w/ a couple of branches, but I'll get up to 6 horses hitched onto it at once. I have also downgraded the light, now I just use a small cfl (horita 23w) horses don't need light, the spounge doesn't need light, I have ogo, which seems to better in less light. it helps to keep the nusance algea down. I've still got some, but it's manageable now.
