Fish Numbers In 50L Temperate Tank

How long is the tank? The fish search thingy on here has a box to tick for unheated tanks. Have you tried that?

The tank is 60cm long. It currently holds 1 male platy and some peppered cory.
I had a look on the community creator at small fish, similar size to the male v. platy, suitable for my water. I've narrowed it down to either getting more male platy to make up the numbers, or wcmm. My concern is that if I introduce more male platy will they start fighting, or would that only happen if they were competing for females? If I get a group of wcmm will the male platy still be on his own, or will the wcmm make it more of a community?
The females in the other tank, with peppered cory and zebra/leopard danio all swim together and all fish seem to get on.
I'm feeling a bit sorry for daddy fish, but not enough to risk more babies. 

Ok, that's settled then, wcmm it is. Thanks for the info.
I only have the one male platy due to being sold unsuitable numbers of fish originally by P@H. At the time I didn't know how to sex them, and now I have more than I started with, but still only 1 male, who I refuse to let back into the other tank, so I've had to set up a temperate tank for him. I got some peppered cory last month, so I'll get some wcmm this month and that will be that tank finished.
Hopefully the wcmm will be peaceful but active enough to get daddy fish to be part of their gang, fingers crossed. 

Thanks for the reassurance.
He has been on his own for several months now and has been ok, but has turned into a bit of a diva as far as food is concerned - completely ignores everything apart from bloodworms. As he's been on his own I have given in to him a lot, hand feeding him bloodworms whilst telling him he's lovely, etc.
I'm hoping that a more active tank will take his mind off the personal treatment.....or at least stop me from doing it.