I use a Z700 The Z740 is the next step up but basically the same camera. To take pictures of my tank I use the Flower symbol setting for object closer than 24" . Get as close to the glass as you can and don't use a flash. When you take a picture make sure your only using the actual optical zoom. Once you get into the digital zoom it will get fuzzy. hold the shutter button half way down and you should get a couple of green brackets. If the fish is in the brackets take the picture and you should be good. It takes some practice, but you'll figure it out. Here are a couple of pics from my camera.
