^Water interface whether it's with glass or without is always a bitch. Don't know if you used a polarizing filter, if not I really recommend buying one. A good one will set you back about 50 bucks but it's well worth it. Helps a lot with the reflections. In a difficult lighting conditions it's a bit of a double edged sword though because it drops an aperture or two basically acting as a gray filter as well. Though it exaggerates the contrast a bit so it may be helpful at times as well. Dirty glass is something you can do very little about and in aquariums it's a constant problem due to alga alone. So very nice considering the environmental aspects. I tried photographing in an aquarium once and got frustrated in something like 3 seconds.
Overall I can't believe that I didn't find this thread sooner. I really like some of your pictures. White balance maybe needs a bit work but it's actually not a huge issue IMO. I like playing around with it and almost never use completely neutral white balance. If you have time and constant lighting conditions (so you can take several pictures) an easy way to get a neutral white balance is with grey card. I think you can still find them in photography stores though they see nowadays less and less of use. Just take one picture with the graycard as close to the subject as possible and with similar lighting. Photoshop has automatic color level adjustment for graycard and you can easily save it as an action and then apply to the actual picture. You'll naturally need to use manual white balance, aperture and shutter speed. Otherwise you'll get quite random results.
Anyway greetings to a fellow photographer.
Seems I can't give you cookies yet but I'll save them for later.