Sick guppy

Question
Hi we got three male guppies in a 10 gallon tank with 2 platys and one loach.  We got them 6 weeks ago, in perfect health.  I do weekly water changes 25%, check amonnia and ph and all seems fine... One of the guppies is a juvenile who is being harrassed and flagged by an older guppy who is seeking to mate with him.  He has become listless and was rapidly mouth breathing and now tail fin is sliced.  Staying at bottom of tank until I moved him to a one gallon tank and added melafix...  Now swimming around, though not touching food and remaining up top with mouth breathing.  I used water from tank as well as gravel and have not added filter.  Not sure what to do with him...
Also, now older guppy is flagging baby male guppy and following him around constantly.  My tank is too small for adding any females and I wasn't interested in breeding.
Can you help?

Answer
Hi Michele,
All you can do is try your best to curb some of the aggression by providing refuges and breaking up the line of sight from one another by putting plants in the aquarium. Keeping a larger group of males can sometimes help because the pecking order and "chasing" will be distributed among the many fish. But then again there does arise severe bullies among male guppies. This will of course be especially more severe in small aquariums like yours. Sometimes you may have to take the bully out for a while and return him to the tank later, or re-arrange the tank decorations to confuse the fish somewhat. But even then it probably won't work long-term as male guppies can just be plain bullies. You may have to take that fish to the petstore if all else fails.

Sorry for the bad news, I hope this helps!
Karen~