Thank you very much for the advice Maroun.c, Here is a few I have come up with and I am much happier at the moment.
These were all taken at 800 ISO 300mm and I took them from the side of the tank where it was flat so the bow front didn't interfere.
F/8 1/50
F/10 1/40
F/13 1/30
F/13 1/40
I had a Whole lot more but these were my favorites out of this set just slight changes really.
Thanks again for everyones help, and as always anymore advice would be appreciated.
Lucas