The seahorse doesn't actually take up more space. For example: I first bought it and put it in my sales tank. I was eventually (not sure how long this took) able to put 20 fish in with the seahorse. Once I moved the seahorse to another tank, I was able to put 21 fish in the sales tank.

I'm not sure when exactly this happened, I just noticed one day that I had 21 fish for sale. I tried it with different tanks, and the same thing happened. So it doesn't actually take up more space. Any thoughts?