trying to do a search I didn't see this come up. When it's recommend that a certain fish is required for a 100 gallon; is that really the tank or the water volume for swimming? once you put in sand and rock, the swimming volume is reduced quite a bit. just curious. I'm not planning on squeezing something in, just after getting a larger tank, I noticed the actual water volume (especially with rock design) is much smaller. Also makes me wonder about the swimming just left to right vs meandering over a more expanse depth. (seriously? depth? I always think depth is height)