That's excellent. Something is irritating them. What?
I have a corner bowfront tank. It is tough to get pictures, but not impossible. You have to get in real close and be perpendicular with the specimen. Then zoom in a close as you can without losing focus, then snap away. Always take 2-5 pictures of each specimen, then only keep the good pics. Blurry pics are good for abstract art and the recycle bin.
Be sure to set the camera to macro mode when snapping your pics. Take some with and without flash.