[DeNovo1]

Happy Friday! So originally I was going to separate my 20 long into two betta tanks but decided to let Rory rule over the the whole 20 long and give him company. I've added some (5) small (younger) bandit Cories, and 5 ember tetras. My question is: when can you breathe and be as assured as possible (and I know things can change, and it's not a given), that your beta doesnt intend to murder all the tank mates? Rory hasn't flared at anyone and although he goes towards them, I certainly wouldn't call it chasing. He swims off, does his own thing and definitely isn't focused on his new tank mates. I guess what I am asking is if there is a rule of thumb that if they are seemingly okay for a certain length of time that you are out of high probability window for it turning horrible? Does that make sense?

 

[JackTheCaptain]

I personally think that since he's not flaring, you're golden. Is he a nest builder? If not, I'm of the mind that he is a relaxed boy, and not territorial.

If however that changes and he starts to nestbuild, flare and appear aggressive, of course all bets are off and whoever he has in his sights will be at risk.