I wanna try to make something that looks similar to a volcano for the centerpiece in my new tank to be. I want it to be about 15" high and have a diameter of around 6". I want a hole in the top since I'm putting an under-gravel air pump and a red LED
light in the middle of it, and maybe some holes here and there for the fish to travel trough. I was considering buying a bunch of lava rock, cutting pieces up, and attaching them together with silicone. Does this sound like a plausible idea, or does everyone think this would be near to impossible? If anyone can think of a rock that's much easier to sculpt, please let me know.