Beginner Gardening: Yellowing Diffenbachia, 1 by BeniJ

BeniJ wrote:
I have 3 stalks of 3 different types of this plant in one pot. The 2 tallest are about 10 to 12in., the least of the stalks has lost all it's leaves and is just a stem. The leaves are becoming pale and they grow in a 8in pot. I dont believe i overwatered. It gets water on average of once every 7 days.Should I keep removing the yellow leaves or let them fall naturally? Should I apply some kind of fertilizer or just leave them alone. Any advice for me?