I have used Philodendron for years, inside and outside the tank. With inside I mean the plant fully submerged in the water, just floating around as it pleases. With that way I never noticed any growing of the plant, although the fish tried to nibble on it here and there, a few bite marks, but they pretty much left it alone.
Now, with outside the tank I mean just the roots dangling in the tank water, the rest of the plant is outside, growing on top and around the tank. Given some kind of indirect light, either close to a window or some growing light hanging above the tank, the plant does really well, and keeps on growing like nuts. I have to cut it down to keep it in shape....