I currently have 8 relatively large pond comets and common goldfish in my outdoor pond..they range from 3-5 inches in size and I was wondering in a 300 gallon pond with plenty of filteration, lillies and cat tails what are some good "mates" to add to the pond..any suggestions? Thanks

For a sparkle of color, did you look at shubunkins? They are basically calico comets, and are equally pond hardy as well!

Will look into those..was thinking more along the line of other kinds of fish non-goldies..do algae eaters fend well in ponds? I'm guessing not due to water temps plenty of food for them thats for sure anyone else?

I guess Im a purist when it comes to goldfish; I prefer to keep species tanks only. Most algae eaters arent a great idea for ponds. Most of them will actually suck onto the goldfish and injure them. Also most of them are tropical and wont survive the winter in the pond. One really good algae eater that I usually recommend for ponds are called high-fin banded loaches. They are a small silver and black striped loach. They have the ability to get huge though and Ive heard they can get up to 3 feet long! Also just make sure they have plenty of algae to eat. Like any algae eater they can starve to death.

As for other fish there really isnt a whole lot. You could try golden orfe or different minnow types, if you want. Usually they are sold as feeders and I thin the orfe are sold at bait shops. Hope this helps!

Will look into the loaches as for more fish I've decided on shubunkins thanks to ranchugirl or possibly some more comets..I had a small feeder .10 cents that had a hint of red..about 6 inches now a very prominant female beautiful colors

I have Koi and Comets in my pond but I also have Oranda's, Ryunkins, Lionheads and a Ranchu. I just bring them inside for the winter as they don't do well in the cold.

I wouldn't get a koi since females need at least 700 gallons
and lots of filtrations,and for males they need 500 gallons.
Did you ever considered putting in some kinds of fancy goldfish
and of course you will have to bring them in,in the winter.

I was considering mostly fish that are hardy and can withstand moderate winters..in Southern California it rarely drops in a large temp difference in the winter..fancies I'm not sure will survive