What's wrong with my goldfish..

Hi all , i'm not sure what my goldfish is doing ..or if she is dead or not. 4 days ago she took a 'fit' in the tank and banged herself into both sides a few times. Banged her sides up pretty good badly, her sides were red down most of the length of her sides. I have been doing a 12 gallon water change daily and adding salt..as i'm not sure what else to have done since I figured she had just bruised herself. With rest and clean water, she would recover again..but today she is acting very..weird, and my other goldfish won't go near her.

for most of the night she had stayed at the bottom of the tank on her side, gasping. my mom said she had been fine most of the night and suddenly she went over on her side and sunk down but now i'm not sure if she's even dead or not. Now she is at the serface with her mouth open but she's barely breathing but I..can't tell if she's passed away or not or what.. What happened?

Now she is just floating at the top , should l just consider her passed on and clean the tank for the sake of the other goldfish or what ? it's starting to make me feel horrible as a fish owner since I don't know what to do..

could she have paralyzed herself?

yikes, if the goldfish is not responding to anything I'd pronounce T.O.D. IF it does move, I'd say euthanize. I don't think it's the injuries cause paralysis. Since there is bruising it was probably something like internal bleeding or some organ damage.

4 days ago she took a 'fit' in the tank and banged herself into both sides a few times.

Can someone tell me what "fit" means?

Hi..
Well, she passed away but I think fishface30 might be right..she could have hurt herself on the inside from what she did. And kimberlyk, by ' fit' I meant she went nuts in the tank and started swimming from side to side banging into things, I call it a fit because I didn't know what else it was Lol

yeah ok, I'd call that a fit too..lol..But, what makes a fish do that to begin with?

did something spook it? perhaps shock(temperature, water quality)? I'm leaning towards spook, since none of the other fish were affected. My dad once had a large red devil, like 10" long, and in the neighborhood a house blew up from a gas explosion. The explosion's shock waves spooked the fish, and it rammed the glass head on, causing something along the lines of brain injury, and died.

Well..it could have been a shock from a few things, but 4 days ago when she first swam into the side of the tank..I don't think anything was weird..I might have had to clean the tank from a little overfeeding and didn't want to..and she might have been upset over that. It has happened before, just not to this extent lol
And then yesterday I discovered the plug/ fuse I had my goldfish hooked up to for power ( air pump, heater, filter..) had gone out for some reason and that couldn't have helped her since the water thus got cool from the heater being off.
Other than that, I can't really think of anything that would push her over an edge into dying.

Goldfish are a cool water fish , so the tank cooling down should not have caused that . It sounds like she had an internal parasite that finally developed to a point that made her try to relive herself by rubbing/banging into things . By that time it would have been too late for it .
Sorry for your loss .
Ray

so then it's possible the tank is infected? best way to find out is to autopsy the fish using web sources to ID parasitic signs.

perhaps your fish's lateral line was damaged somehow which would explain it having a fit.

also maybe im rather ruthless/cold blooded, but if i see a fish that isnt acting right i always quarantine it for a lil while. after that often times when it doesnt recover i usually just sacrifice it. medicating isnt something i like to do because its expensive and sometimes can have side-effects if you medicated the whole tank. if you really want to medicate use medicated food in your quarantine tank so the fish you want medicated gets medicated so you dont mess up your main tank. a gentle way of euthanization is putting it in the freezer; that usually does the trick.

but then again this is normal practice for most fish keepers and breeders, culling poor stock is common place. just ask any Discus breeder

you said "And then yesterday I discovered the plug/ fuse I had my goldfish hooked up to for power ( air pump, heater, filter..) had gone out for some reason" now, this is just my 2 cents, but could the heater have shocked her, causing her to go ballistic, if it did, it would've done what you're talking about, I think.

i was thinking the same thing, but it should messed with the other fish if it was electrical and would shocked her if she put her hands in. Did a circuit breaker or wall socket fuse shut off?
im assuming she checked her equipment visually and everything is in working order now?
is your equipment hooked up to a power strip? if it not i highly recommend getting a rated/certified surge protector rather than using sockets and simple socket expansions. they cost less than 10$ for a decent one at walmart

Had the electrical problem caused it , then all the fish in the system would have been effected .
I still think it was an internal parasite thing .
Just my 2 cents ,,, Ray

I didn't know, we recently had our Pacu bust the heater in our tank, (didn't kill the fish) but it did flip both the power stirp and the breaker.

Well...I thought goldfish were more resillient than freaking out over a heater not being plugged in, in theory but anything could have done her in. I probably won't know what had done her in as she looked healthy more or less when I buried her ( she was waaaay to big to flush). The plug and power strip actually do not work anymore ! I wonder if I had a power serge at my house and didn't notice it as my house does have some electircal problems.. but again.. I don't think equipment failure could have really...really killed her, as my other goldfish seems totally fine .