Captwho, I'd think you should be planting grass around your pond regardless of when you want to stock. Any erosion is just flowing, uncompacted into your pond reducing your water volume with less depth, plus it is an easily disturbed silt that will muddy your water very easily with wind/wave action....or even with trout swimming fast, low in the water column.

Generally, it is suggested that grass seed be planted immediately after any dirt work is ceased in all disturbed areas.