(I used to frequent their forums before their goofy software drove us away, years ago. I have nothing to do with the freshwater fishes stuff though.)
We also do have some thoughts and suggestions vis-a-vis fin rot. Take a look in Immediate Help.
I hadn't though about line of sight to a female tank and male rivalry. That is interesting!
Guppy males are quite benign compared to many fish, though there may be a bad actor. The bad actor is as likely a female as a male.
Water quality also can influence aggression and rncourage it if dirty. (Sometimes there seems no end to the problems brought about by pollution.) This time of the year, as aquarium temperatures climb, some fish become more aggressive. Time outs for heat generating lights may be in order. Service for that drinking water bottle full of frozen tap water may even be called for. ;)
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