Hello. I have 10 tropical fish (tetras and some others). I've had the tetras since 2015 and recently purchased the others a week ago. I would love to aquascape the tank, but do not want to cause stress to the fish by moving them to another smaller tank while I decorate the tank. I want some opinions please. Do you think I should proceed or it's not worth it? Right now the tank is very basic with gravel only and a big rock and medium treehouse-like structure. Nothing else, besides the heater, lights, filter, etc.

I don't normally remove the fish to rescape the tank. It depends how much you want to do though. If you're replacing the substrate you will (of course) need to remove the fish while you do it. But if you're just wanting to put in some decor or add some plants you can very carefully do it with the fish still in the tank.