Thats how i usually use the camera and most photos come out just fine. I normally use a film SLR but then I would have to wait till the photos develop and then scan them and upload them so I'd obviously rather use this.
I normally use an SLR for photography (non-digital ) so I know about TV and AV settings. I dont think that the shutter speed is the problem though, because its not just that fish come out blurry. The whole photo comes out not crisp and clear. I though that maybe it is a problem with the light settings. I'll keep experimenting.