If you've only had them for a week and they came from a shop, they are probably juveniles. Most of the fish in shops are youngsters. Breeders like to move them on as soon as they can as it costs money to keep them till they're fully grown.
Young fish just put into strange surroundings will take a while to settle in and start fighting, but it'll quite likely happen before too long.
+1
liamhuckle
Take back three of them back to the shop and get three females. Then you'll have your centrepiece fish. I'd say that your male will grow to one and a half his current size.
If you get him also some floating plants, when they grow up you might even get them to breed.
As for the rest, as I said, get some more neons, and a few kuhlis.