this is the best one I've found....
http://www.alysta.com/books/fishtank.htm">http://www.alysta.com/books/fishtank.htm</a>
also this one is good...
[IMG]http://www.cichlid-forum.com/articles/aquarium_sizes.php">http://www.cichlid-forum.com/articles/aquarium_sizes.php</a>