Oh yes. Arthur is a very aggressive, feisty sort of personality and he lives in a 4-way-divided 10 gallon without any sort of issues with his neighbors.....his 'evil twin' on the other hand is a different story
. He and Merlin only noticed each other briefly when I first introduced him, but I'm pretty sure he has no idea Bruce is on his other side. Likewise, Mephisto and Bruce seem to be completely unaware that they have tankmates at all.
So I'm pretty sure that if they can see each other, its just barely with the doubled-up mesh. Though now that the dividers have grown a nice bit of algae no one can see each other at all no matter how hard they try.
Lol, well since I've started doubling up on the craft mesh and fitting the dividers a little more snugly/precisely I've had absolutely no issues with anyone sneaking over, so I'd like to think that I've figured out a way to at least minimize that issue. xD I don't know of anyone else who has tried this method yet though, so if you decide to try it, I'd love to hear how it works for you!