also unless you know for a fact that they are a pair,(which is hard to tell),I wouldnt recamend buying 2. you should usually just buy 1 or atleast 3 to develop a small school of them skipping the problems of having the 2 fighting. Aswell as the more of them you have the easier it will to be for them to adjust to your tank having others around since they are schooling fish. Also that is true about firefish being shy which they are very shy usually at first but will eventually learn to stay out more. Might i also add that they are jumpers as well. Sorry to say that I have had one jump out on me so be sure to check around your tank if not fully covered. Also a suggestion is to check in the overflow if you have one because 9 times out of 10 when one goes missing I always find it in the overflow. Be sure to tell us if you see it. I just sure hope you dont find it on the floor.