Last week when I had to bring all 3 of my bettas to my parents' house because of the hurricane, I set them each up with small temporary tanks, all next to each other on the counter. Jasper, my female, was able to see Shiny through the flat sides of their tanks and she got vertical breeding stripes! At first I was wondering why she all of a sudden had them, but then I realized she was only inches from Shiny in his own tank. I had to put up a piece of paper so they couldn't see each other, and then her stripes faded. It was so interesting.