So my male is currently in a divided ten gallon, but I can't fill it all the way up or he runs and hides, too much space, I'm assuming, it's well planted, but whenever I fill it to over 6 gallons, he gets weird and won't come out from behind a pot until the water level goes back down. I'm also hoping to get a second betta, which is why I divided the tank, but the idea of a divider scares me, I keep having visions on fish breaking through in the middle of the night. So I've decided to order a couple of critter keepers off Amazon, the large 3gal ones.
My question is, for people that have used these, are they really 3 gallon? And are they durable, or crack at the slightest bump? How difficult is it to fit in a filter and heater through the lid?