Hi
@duppiman and welcome. Colocasia can be a bit of a pain as indoor plants. Whereabouts are you? I don't believe light is the issue either. If you can't replicate outdoor summer growing conditions then the normal rules don't apply. A photo of the plants in their pots would be helpful. I'd definitely follow Hetty's advice about the tray. Have the plants been outdoors and recently brought in?
Where I am a few hours of direct sunlight does them good. For over wintering indoors the soil should be very well draining and airy. Good soil aeration helps a lot in preventing tuber rot while the plants are sulking (50/50 potting soil/perlite). The plants should be under-potted which will help keep the soil on the dry side. Too large a pot and the soil will remain too wet. I've made both mistakes.
