In my 66 gallon planted tank, I have four fancy goldfish, 7 white cloud moutain minnows and 1 bristlenose pleco (ancistrus).
This combination has worked out very well for me. The ancistrus is an excellent algae eater. They have good appetites and you should supplement their food with algae wafers and blanched veggies.
White cloud mountain minnows come in two colours, beige and gold. Both are very pretty. They prefer cooler temperatures so are good with fancy goldfish. They have the same requirements for diet, as well, however I generally give the white clouds some flake food while the goldfish are occupied with their food. The white clouds like to take their food either from the surface or when it is floating down through the water. They don't pick off the bottom like goldfish. They pretty well stick to the upper levels of the tank. They like to be kept in a small group, so a shoal of at least 5 is a good number.
Hope this helps and please feel free to ask questions