I have not been able to snag a picture, so i hope my description will point me in the right direction.
I have seen this fish on lake lewisville, in a cove, in water about 18 ft deep.
I have always seen this fish on the surface, doing something that looks like barrel roll.
The coloring seems to be a yellowish green on the bottom and i think it is getting darker towards the top.
I would guess the length is about 2 feet long.

Any ideas? or perhaps just a chart of possible fish i could look through and see what seems close.

Thanks

Carp!

Most likely it's a 'carp'

https://www.google.com/search?q=texas+ca...mp;ved=0CDUQ7Ak

http://www.tpwd.state.tx.us/landwater/water/aquaticspecies/inland.phtml

Carp

Are there alligator gar up there?

Would be my guess!

Gar and they are porpoising. Most are probably longer than 2 ft, you are just seeing their snouts.

18 fow? I say Gar.

Gar or carp they will come to the surface and roll.

Carp

I think Carp is the answer. I had not really considered them as i thought they mostly stuck to the bottom. I also did not know they were that greenish yellow.
Is there anything i can cast that they will be interested in? some type of surface lure perhaps.

i dont think they are the snouts of Gar, i have definately seen fins

Gar

I see gar on LL quite often, active on the surface

Carp will either feed on the top or bottom, and you usually have to bait the area to bring them in. After saying that, sweet corn on a smaller hook works well. For the size of fish they are, their mouths are kind of on the smaller side.

Garp