Now the negative part and you may already know this. Once they grow up some you are going to need to get a larger tank or get rid of one of your fish. A 55 gallon is the minimum size for an adult Oscar solo. You have a few months before you have to make a decision though.
For better pictures put a bright light on top of the aquarium pointing down instead of using the camera flash. You can also try to take the pictures at an angle. When I was using a point and shoot I would cover the flash with some tissue paper to diffuse it and shoot at an angle. Sometimes they would come out pretty well.
I would guess male on the GT too. With that much orange on its tail allready I would guess male. I have a little GT with a bunch of orange. I hope male for the both of us. Those two should go for awhile in that tank, but a year or so down the road you will probably be wanting to look at a 125 as they can both hit 10" plus eventually. Nice looking tank!
Nice fish! Honestly it's difficult to get good pictures of fish. I've taught myself to be very patient, sit still, and maybe I'll get a few good pictures out of 100. Thank goodness for digital cameras.
For settings, I set my camera to "Manual". I pick "Macro" and "Iso400", no flash. You can also fool around with the color settings until you get the ones that look most accurate for your fish. Turn off all the lights in the room except for the tank light, sit still, and wait for your fish to get comfortable with the camera.