Welcome to AC, My_Goldie. :welcome:
Many of us here share your interest in goldfish. I'm glad you've found your way to our site and this forum.
My goldfish, Goldie, had an incident this morning (got stuck inside one of the decorations) and is pretty banged up now. He's scraped off scales and skin along one whole side of his head and it's the worst on his gill plate.
Goldfish are very inquisitive and manage to squeeze themselves into very tight places. They're a very wiggly fish that are good at surprising us like that. Of course, they're not real good at figuring out how to get back out again. I hope you've already removed that decor item from the tank. Try also to avoid anything else that has rough surfaces, sharp edges, and other tight places that may cause harm to your fish.
He was stuck, and I pushed him out carefully and now he is very lethargic and just kind of sits, and doesn't seem totally there. He gets random bursts of energy but also keep sitting towards the top or bottom of the tank.
A superficial external wound from a minor scrape on the side of a goldfish should heal itself well in a matter of days to a week or so. But given the circumstances and the extent of damage that you describe (scraped off skin), he should be quarantined to a smaller tank where you can treat the wounded fish better (aquarium salt and melafix as already recommended)... watch him now for the onset of infection, fungus, and so on... and keep him in a less stressful environment that he needs for recovery. Adding some stress-coat, as well, will help replace the natural slime coating around his open wounds. The slime coat is his way of fending off both infection and parasites, to which he is especially vulnerable right now.
I'm thinking he's not doing so well, and was just wondering if there was anything I could do for him.
I share your concern here. The injury itself should heal quickly, but he's at a very high risk now for other complications which may set in as a result of the wound and his distressed condition.
I don't have a cycled quarantine tank, and don't want to take the chance of moving him to an uncycled tank.
You need to get one. If you've got a 50 gallon tank with 4 fish in it, you need to have a quarantine tank on hand (or something else suitable) to isolate a fish in a hurry when an emergency comes up. You've just found out why this morning.
Very few quarantine tanks are already cycled. If they were, they'd be inhabited with other fish already and, thus, unavailable for use when a need arises. While using one for a sick or injured fish, you'll be doing frequent water changes anyway to keep the environment clean and to medicate the fish properly. It's also much cheaper for you to treat 10 gallons at a time than 50 gallons.
The other 2 guys in the tank aren't messing with him at all, and neither is the pleco.
I wouldn't expect so, yet. This just happened today. Even so, that fish is weak, lethargic, and wounded now and he will be for many days to come. He's a prime candidate for even the most peaceful fish to start picking at him, especially when he's resting. It's not safe for him in the same tank with the others in his present condition.
Oh and I have a 50 gallon tank with 3 goldfish and a pleco.
Three small goldfish may outgrow a 50 gallon tank within a short period of time. Which types of goldfish are they? If they're 3 black moors or another type of smaller (adult sized) goldfish, they should be okay to stay there together. But large bodied varieties (such as comets, fantails, or orandas) would become overcrowded there.
You have something else to consider about your present setup. Goldfish and plecos do not make suitable tankmates. If it was a fish store who sold you these 4 together, I would not seek out their advice on either goldfish or tropicals in the future. Both kinds are extremely messy fish that produce a high amount of waste. So the pleco adds more to the bio-load than he helps you with algae control. Besides which, plecos need warm water conditions while goldfish need a cold water environment. There is no safe overlap in between where either the goldfish or the pleco (or both) would thrive over the long term. The slime coating on goldfish and other high-bodied varieties is also very appealing to most suckerfish, like plecos. If (or when) the pleco decides to choose this slime over algae, your goldfish are in real danger. They are most vulnerable when they sleep. Further, the healthy green form of algae which gets consumed by the pleco won't be there for the goldfish to graze on, which they do.
Please look through the information found here:
http://www.goldfishconnection.com/articles/details.php?articleId=153&parentId=1
http://www.goldfishconnection.com/articles/details.php?articleId=144&parentId=1