Hi William,
All your pictures are spot on technically. It is clear that you are really on top of the rebel now and producing consistently good results.
I think all the images could be improved with a bit more attention to produce interesting compositions (there are a lot of centre AF bullseye compositions here) and in quite a few images you have chopped bits off the subjects when there is plenty of room in the frame not too.
I know this sounds negative - but the images are spot on technically so now its up to you to do more with your photography. Its clear that your technical skills are there to produce some really stunning shots.
I think you should be concentrating more on what you are trying to communicate with the image. What is the image about? What is the story it is telling? Exploit the space in your frame with your compositions and put the subject in areas that the viewer may not expect (like the head of the pipefish).
I hope that you take these comments as encouragement. I really like your images, but you are on the GBR and have a fantastic camera that you clearly know how to use. A little bit more consideration when you are putting your images together and you will be producing shots that stand way above most you see on the web.
Best regards,
Alex