Youll be very lucky if the loach does eat the wafers, i found they prefer to stay on the glass or browse on the brown algae on rocks.
You will need a fast air flow pointing onto one of the tank walls and have it with air going through.
The hillstream comes from fast flowing streams and these are well oxygenated. They dont grow very big, maybe 3 inches at most but are really fast when they want to be. As long as the goldies arent monsters then they should get on ok.
If you want to try and feed half an algae tablet then add when the tank is dark and the goldies are sleeping.