I originally started with my betta and when I added the cory cats he tried to charge them. It was hilarious because the albino cories just went right through him like he didn't exist. He learned really fast that there was no point. When I moved them to a larger tank, I moved all the cories and a few other new fish to my new tank and left the betta in its old tank. He was miserable ( seriously). I waited a week and then placed him in a breeding floating tank in the large tank. He was okay for a day so I placed him in the main tank. Because he was the last added, he just found a comfortable spot ( ironically right above where the cories settled in) and stayed there. Now they get along well. I would say it is kind of like putting a dog and a cat together. The cories are happy to hang out with the betta, the betta seems to put up with the cories ( until you aren't looking and then he snuggles up to them - really!). I will always put cories and bettas together - but I think it has to do with how you go about putting them together. If the betta goes in last after everyone else has settled, he can't fight for his territory, because it isn't his. At least this is how I see it. My betta is really happy in my tank, along with his tank mates. Good luck.
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