[untamed]

Also...if there are holes in the back wall of the tank inside the overflow boxes...then I don't see any need for the overflow boxes to be full length to the bottom of the tank. The main reason for an overflow box to go right to the tank bottom would be if the holes were drilled in the tank bottom.

Shortening the internal overflow boxes would create a sheltered area underneath that could house sponges or other critters that don't like light. Fish would also probably like to hang out under there.

Now...for the "out there" idea... If you created a full-to-the-bottom overflow box, with the holes in the back wall as already designed.... you could open one side of the overflow box at the bottom. This would create a sheltered area inside the overflow box. If you are lucky, this could be used as a fish trap. Fish go in..block the hole...net the fish from the top.

I do wish I had incorporated some sort of fish capture mechanism in my tank design. I would probably still have my white cheek Tang if I had done that.