What type algae eater do you have? Adult Chinese algae eaters can be very aggressive. Goldfish really shouldn't be kept with other types of fish, particularly tropicals. Not overfeeding, reducing light levels, and doing your water changes on a regular schedule is the best way to keep the algae out of the tank. As far as your injured fish, I am not a big proponent of using meds, although I guess at times they are useful. I would just be sure the water is kept pristine while the wound heals. Maybe others have had good success with meds, but since I don't use them, I can't really say.

We used meds all the time at the wholesaler I worked for. But then again, when you're receiving 200 platys in a small bag, travelling for a few days, ya need it. Tetracycline works the best for bacterial infections, stopping the infection in its tracks. After a couple days on meds, a water change should be done. If the fish still displays symptoms, add more TC.

Check Goldfishconnection.com, suggests NEVER keep algae eaters with goldfish, they will kill your goldfish. It's a great site! Good luck!
Shelley