The female Borealis get to be about the size of a male Laevis (with male Borealis even a bit smaller). The Tropicalis even a bit smaller than that. If these are 20 gallon longs I wouldn't blink at putting 6 -7 frogs in them. In my experience the Tropicalis are not nearly as active. They hide in a cave, they perch in the plants, the hide behind the filter, they perch in the plants and that's about it lol.