Originally Posted by gn3ranger
@reggie my betta literally would lunge at the cories moving the gravel when he missed them making rocks move everywhere he never got a shot on my cories but i saw his intentions and i will not take the chance of not dividing them. I've never seen him puff his gills out like that I thought he was sick but as said above its just territorial. Plus it kinda makes me sad seeing the innocent cories scavenging for food minding their own business and then wam betta attack. :(
Yes. Besides, the betta aggresion may not be posing real direct danger for the corys, but certainly stresses them making your corys prone to diseases. I wish I could tell you about the Q about betta becoming aggressive under certain conditions, but my knowledge is insufficient on this subject.