There wasn't a truly bad photo in the bunch. I almost picked #13 too because it's technically perfect. Certainly nothing wrong with that, but it was almost stock photo-esque in its perfection IMO and I have a personal preference for seeing the fish in their environment. Almost went for #4 too but the female of the (exquisite) HRP pair was a bit out of focus. I liked how they were framed by the branches. I also loved #16 because the composition was great and it was a lovely photo of a lovely angelfish in a lovely setting. But the image quality wasn't quite sharp enough when compared to some of the competition. That's one area where great (often painfully expensive) lenses and lighting can give competitors an edge regardless of other factors. Ultimately I settled on #7 because it was beautifully composed and sharp, it showed the pleco in motion and the setting was gorgeous. It had what #13 had, but with a natural pose, color and a great backdrop which still allowed the beauty of the fish to take center stage.
These days I rarely bother to get out my trusty DSLR and I really should rather than taking half-hearted phone snapshots, but I always enjoyed hearing constructive criticism from my teachers and peers with different opinions about my photos so I hope others do too and don't take offense. I learned so much from hearing others' perspectives.
Part of this is that photography is half technical and half subjective. For example, I can't argue with the obvious skill and careful setup behind #13. But #4, #7 and #16 all made me smile. #7 ticked all of the boxes for both technicality *and* visual interest. The latter is the subjective part which is mostly in the eye of the viewer and to which the photographer is at the mercy of his or her audience.
Hope that's helpful and encouraging, as it was intended. It's not a slight to any of the exceptional group we have this month, which made the choice one that I had to put a lot of thought into.
I went with thirteen too due to the content and quality of the image. Many of the pictures were really good and I could have gone with a couple of others and been satisfied with my choice. Thank you for sharing folks!
I had to look at them all multiple times to make a decision. 13 actually took me a minute to realize what I was looking at. Probably because I usually look at this on my phone. But that is like others have said a superb technically taken photo. I didnt vote for that one because probably like others it wasnt visually appealing. But that is a cool photo and one of the rightful winners.