if 2 males are chasing each other, it can mean three thing: one male wants to chase another male away from a female, both are playing or one is bullying the other

the way to find which one it is...if it is bullying one fish will be completely breathless, will remain hiding from the other fish

if it is playing, each will take turns chasing each other, the roles will change, each taking turns to "get" one another

if it is territorial or protecting a female fish, then it is almost like bullying, and you will have a problem on your hand

unless the molly gets injured, I wouldn't be too worried about it...usually bullying is a display of the pecking order, one fish will gain the upper hand over the other fish like with dogs (if you have one), always a pecking order...sheesh, come to think of it, all animals and humans have pecking orders (((smiles)))

anyway, so unless the fish is injured, don't be too concerned, it will eventually die down...but observe as much as possible...let us know how things develop