In rec.aquaria.freshwater.cichlids Siegfried B?sler wrote:
I often see photos from fishes, they look all egual, because of bullseye
focus. Those kind of photos are usful for books, but the more
interesting photos are photos they tell a story and with a photo you can
initiate that.
But this is my personal opinion.

Well, if I could really be argumentative here, show me which photo of mine
on that page, other than the whole tank shot and the one closeup of the
similis on the blue-grey-green background, that has the fish in the exact
center of focus. With the exception of the two listed, which would look
rather wierd if shot differently IMO, all the others have the fish
off-center in a fuzzy form of the rule of thirds which takes into account
multiple subjects and the backgrounds.

Take the first photo of the similis in the 10gal. He is in the upper third
of the shot, although a little close to center. The rock is in the left
third. The shell is in the right third. The closeup of the fry in front of
the leaves uses the leaves to create the thirds. The fry is somewhat
off-center. The larger leaf takes up 2/3rds of the photo, the small leaves
make up the other third and the fry is at the margins of the two.

As I said in the first post, I could have cropped these photos to an exact
golden rule in several cases (others could not due to the issue of framing
multiple subjects that I also mentioned), but it would have increased
their file size to an extent I found unneccessary given the fact that the
current croppings don't have any of the fish dead smack in the middle of
the photo except for the closeup of the similis. That one is more of a
portrait which would look rather odd, due to the lack of balancing
background, if the fish were not somewhat centered, but even then, it is
not exactly centered.