Hi everyone,
We have a 20-gl tank with 4 goldfish. They are just regular goldfish, only one is smaller and has a chubby tummy (named 'chubby' by my 4 yr old :) We have a nice filter and change their water once a week. We have had them for 1.5 years now, and except for a parasite problem in the first week we got them, there has been no problems - until last night. I found chubby hiding the in the live plant in the evening. He usually sleeps there, but he seemed like he was struggling to get out, so I moved the plant a bit and he got out. He seemed out of sorts, swimming, then stopping, then floating, then struggling against the air bubbles. This morning, we got up to see all his back fin (sorry, my goldfish jargon is quite inept) eaten up, and even saw the larger goldfish with black spots (dalmation is his name) nipping his other fins as well. I can not see any physical problems with chubby, except his tummy's right side seems a bit yellow, but I can't remember whether it's been that was for a while or not.

I took chubby out of the regular aquarium, and put him in a bowl with just some gravel, and added some of his old aquariums water plus some new water and 1 drop if mulvita vitamin. He seems better now, swimming a bit, eating, slightly constipated.. I will go and look for the antibiotic stuff Robyn talked about in her previous replies to try and see whether I can prevent infection, but his back fin is so damaged, I don't think he'll make it... I will also try the pea tomorrow, he has had enough to eat...

Anythimg else I can do? Why did the other fish bite his tail off? Do they hurt each other when one is weak or sick? What sign should I llook for on the other fish to see if they're sick or not? )no parasites apparent, water quality is good, fins look ok etc)

Thanks in advance for your help.

Kindest regards,
Z

Sorry - I reread my post and realized, what I mean by "back fin" is his tail. (!) It's 2 AM and my 1.5 yr old has a cold and neither of us had a good night's sleep in 3 days so that's my excuse :)
z.

"This morning, we got up to see all his back fin (sorry, my goldfish jargon is quite inept) eaten up, and even saw the larger goldfish with black spots (dalmation is his name) nipping his other fins as well. I can not see any physical problems with chubby, except his tummy's right side seems a bit yellow, but I can't remember whether it's been that was for a while or not."

Chubby sounds like he's a fancy goldfish and perhaps the others are not. It is pretty common for goldfish to bite on each others fins especially when mixing fancy goldfish with regular ones. If a goldfish is injured, the others often then almost munch on his injured areas making things worse. I'm sure they don't mean harm but they don't get that they're hurting their buddy. Flowing fins may resemble food to some goldfish. I've noticed yellow patches on some partially white goldfish, especially stressed fancy ones I had years ago.

"I took chubby out of the regular aquarium, and put him in a bowl with just some gravel, and added some of his old aquariums water plus some new water and 1 drop if mulvita vitamin. He seems better now, swimming a bit, eating, slightly constipated.. I will go and look for the antibiotic stuff Robyn talked about in her previous replies to try and see whether I can prevent infection, but his back fin is so damaged, I don't think he'll make it... I will also try the pea tomorrow, he has had enough to eat... "

Try to get Chubby an aquarium of his own if you can. That will help a lot. Antibiotics should help. I don't know if you can get these products where you live but these are what I use for treating physical damage: aquarium salt, Stress-Coat by Aquarium Pharmaceuticals, Maracyn by Mardel, and Mela-Fix by Aquarium Pharmaceuticals.

"Why did the other fish bite his tail off? Do they hurt each other when one is weak or sick?"

Yes, they just do that. I don't know why.

"What sign should I llook for on the other fish to see if they're sick or not? )no parasites apparent, water quality is good, fins look ok etc)"

Look for any abnormal growths or spots, redness, fin loss, fuzziness, strange patches, abnormal behavior, etc. Basically, learn what they normally look like and then look for a change (doesn't work if they were sick when you first looked of course).

Thanks, Robyn,
We live in Istanbul, Turkey, and there is a good auarium supply place where we originally got the fish from. They might not have the same exact brands, but sp,ething comparable.

Chubby is in a separate bowl, but we don't have an actual tank for him, maybe I'll get a 5-10 gallon and keep it for quarantine purposes.

Chubby doesn't look too well - just sitting sort of upside down all day long, but struggling to float upwards for food. We'll see if he'll make it. My husband thinks Im overreacting, but I really like the darn creatures...

Thanks again for the info.. I'll let you know how things go..

Z.

Well, he didn't make it... At least I know we tried our best... Thanks again for your help. z,

Sorry about Chubby.