Taking Aquarium Photos

Been trying to take a decent photo of the fish tanks. So did a lot of research and finally got round to taking it.

1. Get a tripod - check
2. Set to aperture priority and set to lowest aperture possible - check (lowest was 4 on the camera)
3. Set ISO to 400 - check (heck kiasu a bit went on to 800)
4. Switch off all other room lights - check
5. Use manual focus - check
6. Set camera at slightly higher angle - check
7. Forgot anything?Yeah...... how to stop the *&%#%( fish from swimming so that they can stay in focus!