Paradise Fish and Platys - Aggressive Male

[HollieDahhrlinn]

Hello,
I have a 4 gallon tank and 2 paradise fish and 2 platys.
My paradise fish are one of both sex male and female.
My male is becoming aggressive, i am aware he will as he gets older however my plan is to move him when he is at about 1 year old yet he has only been in my tank 3 days yet he is making it hard for my platys to feed. I am alittle reluctant to return him to the pet store as not only will this be stressful - i feel sorry for him, he's just getting settled then returning him is that weird?
Well, is there anything at all i can do to help my other fish and not have to return him?

Please help,
HollieDahhrlinn x