i have a 20 gallon tank, which is well planted and my fish are thriving. so i just added my school of 6 tetras to it and theyve been amazing. today when i fed them, i noticed that one of the largest tetras started to become territorial and wouldnt allow the other tetras in his half of the tank. all the tetras tried to come to his side, but he chased every one of them away but he didnt mess with the corys. so then while the tetra was being territorial, i see another tetra which was about the territorial ones size in a corner by one of my large plants. the territorial tetra didnt mind but if the tetra came out of the corner, the territorial tetra would chase it back. im thinking that theyre about to breed of course, but the whole school is broken now and the outcasted tetras are swimming on the bottom, which they never do. so im debating whether or not to add more tetras. i know my filter could handle it, but i dont want to add stress to the possibly breeding pair of tetras. any advice? i have no idea how to go about these tetras because im a cichlid person. thanks in advance!