I've got no business voicing an opinion regarding a contest I'll never enter, but...wouldn't it be a lot easier if there were simply one contest per month, and then one yearly winner, with no categories or subcategories or restrictions? Complete free-for-all, with only one rule: the photo must be in some way aquarium-related. Aside from that, anything goes; fish pics, tank pics, fish room pics, filter pics, plant pics, pond pics, you name it. If it has any relevance to the aquarium hobby, it's fair game.
Deadeye
has been doing a great job of keeping this ball rolling, so he can be entrusted with the veto regarding those pics that are marginal in terms of acceptabiity. There's always going to be somebody who tries to break/bend/flex the rules a bit, but I think that most people will behave reasonably.
The benefit, IMHO, would be simplicity. Any time that someone happens to get a great shot...whether it's taken with a pro-grade camera and careful preparation and staging, or simply is a lucky grab taken with a cell phone...that pic can immediately be entered for that month's contest. No waiting for the next XXX-of-the-month, no fretting about categories...just look at the pic, say to yourself "I like it!" and send in the entry. Voting and everything else would remain as it is now.
This simplicity would...I think...increase the number of entrants. Or not? I mean, I've been wrong before...