goldfish and bottom feeders outdoor pond

Question
QUESTION: I have just set up a  copper fantail gold fish pond outdoors 3' long 15" wide 9" deep. I have two fantail goldfish and some water hyacinths and an arrowhead plant in it. I was wondering if I need a bottom feeder for algae like in an aquarium? I would like it to be self sufficient.I have one small pump without filter only putting air into the pond. The pond is in the shade under a tree. Sure hope you can give me the answers. Thank you ahead of time.

ANSWER: Hello Char!
An Algae Eater wouldn't hurt, but you did not say what area of the country you live in. Algae Eaters are tropical and cannot stay out in cooler areas. But then...neither can the Goldfish in a bowl.
Japanese Trapdoor snails would do the job, too.

---------- FOLLOW-UP ----------

QUESTION: I live in Texas where the temps can and do get over 100 quite frequently. I was told not to feed the goldies and they would basically eat the algae themselves.I was also told that the Chinese algae eater would eventually get large enough then start attaching itself to the fish in the tank. I would like an established ecosystem eventually. With this in mind, do I need a filter system? Are the same requirements for goldfish the same for Koi? Thanks Bridgett

Answer
It's quite right that you do not want to feed the Goldfish. They will look after themselves. I would probably skip the algae eater.
It is almost impossible, though, to establish a complete eco system in a container that small. Occasionally it will need a helping hand.
Make sure the pump makes quite a bit of splash, because hot water is notoriously low on oxygen.