WCMs aren't really suited to a tropical tank. Also, cories like to be in groups of at least 4 to 5. If it's possible, I would suggest upgrading to a 20 gallon and adding some more cory cats.
My heater automatically heats the water to 76 F and then turns off. I know this is on the higher edge of comfortable conditions for the WCM, but they've been doing just as well as the day I got them. Unfortunately, a 20 gallon tank isn't an option for the immediate future (due to rooming constraints, not financial restrictions), so adding another 3-4 cory's might not be a good idea if you're already concerned about overpopulation in my 10 gallon tank.
1 Male Betta (January 23, 2011)
5 Zebra Dainos (September 4th, 2010)
9 White Cloud Minnows (5 from October 4th 2010, 4 from January 19th, 2011)
1 Pygmy Cory Catfish (September 4th, 2010)
2 Ghost Shrimp (January 19th, 2011)