I add a new betta yesterday to my gang. He has his own tank but I put him next to the others. I had already 2 tanks beside each other and the fishes did not care much about each other. So , I put the new tank next to the 2nd one and after few minutes, I noticed that they were flaring really hard to each other! Plus, it turned out that they have almost the same color pattern. So, I put a cardboard between the tank so they could not see each other anymore. But, gosh! They still flare like crazy! and most of the time, they are face to face without being able to REALLY see each other!! How could they know?? Have you ever seen this? Do they «feel» each other?