Goldfish pecking at another

Question
I have a tank with 2 fancy goldfish and 1 oranda. The oranda is new, it has only been in there about a week. Of the 2 fancy 1 is larger than the other 2 and the other is the same size as the oranda. The smaller fancy goldfish has been acting kind of weird. i don't know if this is related but a few weeks ago he got trapped in a tank decoration, it was one of those bubblers that has a skeleton popping out of a hollowed out log and he was between the skeleton and the log if that makes sense. When I couldn't find him i saw the tip of his tail sticking out the top. I had to break the decoration to get him out, and I didn't touch him, i just broke it and he wiggled out, and he seemed okay right after. For the past few days he'll be swimming fine then suddenly swim in a fast circle like a maniac going upside down sometimes, also he seems a bit lethargic but is still eating. The oranda has started pecking at him, and it's doing it more and more it seems. There looks to be a small spot of scales missing on the fancy goldfish but i don't know if it's from when he was stuck or if he's sick or if it's always been that way. Also, he doesn't seem to be using his right front fin very much, only occasionally, usually it's flat against his side even when swimming. is the oranda just a bully to the smaller of the 2 fancy fish or is the fancy possibly sick or injured? Should i separate them?

Answer
Kristen,  When you add a new fish especially a bigger fish you may have this problem a good way to help this is change around the your decorations. This way they all have to stake out new territory. Unfortunately when your fish was stuck its body was not working normally. The water around him was dirty and he was absorbing it. He sounds like he has gotten abit of a swim bladder infection and is abit constipated. I would do two things. I would add aquarium salt or Epsom salt 1 tsp. per 5 gallons. This is to get help the constipation and is good for everyone. I would also add Melafix it is an all natural broad spectrum antibiotic. Mild but good... fine for everyone. It is nature and survival of the fittest and if someone is sick they do pick. If he doesn't stop picking yes I would separate them. A good rule for your goldie's is at least once a week feed them a thawed out pea or three and crack it put it in and remove shell later. It keeps them regular and gives them greens. Also, with my goldie's if you look at their food it is fortified with vitamin C. This is because they suffer vitamin deficiencies in captivity. Go and get a veggie clip from your pet shop (it is a clip with a suction cup) and slice and orange not too thick and put a slice in half with the rind in and the meat out. They love it and is good for them. You can do this also once a week. Do not leave in for more than an hour or two. Good Luck, Tina