I have had onhe silver aro for about 2 months and I bought another about two weeks ago. Thay are almost identical in size! For the first while they seemed to be best friends, swimming jointly, no problems at all. Just in the last two days my original seems to be getting a little aggressive towards the other. Arching his had back, puffing up his gills, and sometimes even going after the other. Do you think this will go away or should I seperate them, meaning give one away ; (

