I see many of you know what you are doing when taking pics of fish.
I have a Casio which has a 2 sec delay on the flash. By then the fish has moved and the pic is fuzzy.
I DONT USE FLASH WHEN TAKING PICTURES OF FISH IN A TANK BECAUSE THE REFLECTION FROM THE FLASH CAN MAKE IT BLURRY LIKE THAT TRY TURNING THE FLASH OFF AND RAISING THE ISO UP AND TRY THAT