I was wondering what was the end result of your Betta bowl set-up not having the snap-on lid to keep the kitties out should they try to "pet"your fish as you said. So, now, with a male and female betta fish next to each other in separate bowls and the male getting all excited and building bubble nests, as you say, it would be good to have vented lids on each Betta habitat. Bettas are jumpers and the male, for example, could feel determined enough to attempt to jump into her bowl. This could be disastrous because he could
accidentally jump onto the bookshelf and die being outof the water or he could make it into her bowl and kill her since mating Siamese Fighting Fish can be tricky.