I got two clown loaches...?

[aznb0iyz2]

Its been about a month. First few weeks they seemed to be playing around and schooling together and sleep together. But closer to the month mark i notice the one being chases around has a messed up fin..its even and all but doesn't look how it use too. Im thinking the other one that chases him/her around has been bitting the other one... Ive been watching them closely and one chasis the other all the time and it doesnt seem to be play chasing anymore cause they are dashing back and forth like crazy and the one being chased is always pale while the other is dark. While i watch when the one being chased tries to go into the sleep/hiding spot the other one goes in and they start the chasing process all over again. I think when they do go to sleep though they sleep together? maybe not? Is one trying to be the alpha? should i get a third one to balance out? Plz help