I have a black moor goldfish and a gold fancy tailed goldfish. I had to get rid of the last algae eater, because he started eating on the fish. (It had got to be about 8 inches long) I donated it to the pet shop where I bought it. I got a really tiny algae eater, thinking that it would be too small to eat on the fish. Well, no.......That is not the case! It is now eating on the fish. It has take a piece off the black moor's tail, and I believe it did something to the gold ones eye, as the eye is now swollen. I really don't think it's popeye, I think it's an injury from the algae eater. My fish are healthy and happy, and the water quality is great. I make water changes faithfully. My question actually is, should I just get rid of algae eaters all together? Do I really need them? Thanks for any suggestions!

Thanks scrivens345, I appreciate the info. I'm really curious about my gold fantails eye. Do you think it's possible the algae eater did something to it, since the eye really doesn't have a slime coat, or at least I think it dont? She was fine till I added this new algae eater. She seems fine, no stress, eating, swimming, not laying on the bottom, etc, but her poor eye is swollen, and sunk it like it was attacked. Not popeye, or at least I dont think it is. I just caught the algae eater hanging on to the black moor's tail, and the black moor was swimming around trying to get it off him. I say he, and she, cause I think of the black one as a male, and the gold one as a female, but I really don't have any idea how to tell!

You don't need algae eaters at all with goldfish!
I had the same problem, my 18cm pleco starting harassing my fish, not eating them, but attaching them, my poor moor had her pectoral fin shredded, her tail was full of holes and she lost scales in big patches I ended up giving him away too.
And about the swollen eye, my fantails had a bout of breeding frenzy, and one of my guys ended up hurting his eye. The swelling went down in about 5 days on it's own, simply keeping the water quality good

Apple snails are fine to keep with goldfish, tried and true!
But you could try getting first one and seeing how the goldfish react on it, there are people here who had their snails starve to death because the goldfish wouldn't leave them alone.

In general, plecos can be pretty territorial, especially once they grow bigger, the only suckermouth catfish I had any luck with were bristlenoses (common ancistrus), these are fairly small and very friendly, should be kept in a pair or a group of three and they'll mind their own business In case your tank is 10-20 gallons, it will be far too small for a pleco to be comfortable with his allotted space, and he'd be angry and harassing the goldfish when they trespass (constantly looking for food).
You could let algae grow a nice carpet on the back walls and possibly ornaments of the tank. I personally only clean off the algae on the front and occasionally the sides, never the back. The goldfish love grazing on algae!

In the community tank at my parents' place we kept two fantails together before, it's roughly 26 gallons and both lived for many years, happily! And honestly, we weren't even cleaning the tank too much, being n00bs and children looking after them

Heh, someone had problems registering what you said, I suppose! Sort of funny in a sad way though
When I went with mine to my favorite pet shop, knowing that he'd be well taken care of there and get better chances to land in a good home, the guy there understood what it was about right away, and put the pleco together with some cichlids, saying that they'd be more suitable tank mates for him.