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Category: Pet
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Fin damaged on goldfish

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Hi Gina - several months ago you helped me with the ick problem in my tank and my fish were recovered. Now that I observed another problem and will need your help again. The biggest common goldfish is now 2.5 inches long (tail not included). About 2 weeks ago I realized that its anal fin and the pair of pelvic fin are damaged. I mean it's not fin rot but it just looks like it was cut out a piece by a scissor. Then the dorsal fin as well after 2 days. I immediately treat with Melafix, the fin didn't get worse but also not getting any better. It's been over 7 days I treat with Melafix now and I don't know what else I can do. I still keep the routine 30% water change per week.
The fish itself doesn't act different than usual. I also have another comet goldfish losing scales but acts normal. Why is that?
By the way, I took your suggestion and switched to a 10 gallon tank. So I don't think they are stressing.
Thanks Gina.


I remember :) I am glad you got through the ick, but it seems that now you have possible fin rot going on. Make sure you are testing your water just to be on the safe side as you may need to increase the water changes to twice per week depending on how much waste is in the water..goldfish do excrete A LOT, and being in poor water condition causes fin rot and scale loss from stress. I know, I know you switched the tanks (YAY for you) but they can still stress. Most importantly check the ammonia levels and the nitrates. Also, when you do a water change, you should be cleaning the gravel as that is where a lot of food and excretement end up. I use a tool called a looks like a hose with a large tube on the end. It hooks up to my sink and syphones through the stones and removes the water. If you can find one at your local pet shop, and you can reach your tank (usually come in 25-50 ft length) it is well worth the purchase. :) I am glad you are using the melafix..good stuff. There are other products available to treat the fin rot, but all are useless if your water is not perfect. I would also suggest putting in 2 teaspoons of aquarium salt and some stress coat. The fins may grow back together or they may really depends on how extensive the damage is. Also, watch them closely as they may be fighting with each other causing the issues you are seeing..just a thought. :) Let me know if you need further help with this :)

Customer: replied 10 years ago.
Thanks Gina. I test the water. The Nitrate, Nitrite and Ammonia level are zero. So I really don't know what happen. In fact one of the 2 goldfish, the comet has this problem from day one I brought him back. He is losing scales and his fin damaged once in a while and grow back. About 30% of his scales were fell off but he is still doing fine. Now the common goldfish started to have this fin problem. I really don't know why, as I keep the water very clean. (also they don't fight, the comet always follow the common goldfish. very cute!).
Also the common goldfish always float to the surface and stop moving. Is he sleeping? I read some articles that said if fish do that they may be lack of oxygen. But there are 2 power filters and an airstone, so I don't believe the water is lacking oxygen. Any idea? (FYI- he acts like that from day one - 1 year ago when I got him). Is that a problem if fish acts like that?
Thanks again, Gina.


Well, I am at a loss...stumped and boy is that hard for me to admit. I am going to opt out of this one so you can get a good answer that will be helpful. I just can't for the life of me, figure out why this is happening if everything is at zero and they are not fighting. It will be interesting to see what others think, so sit tight and someone will get with you soon. YOu will get email notified when there is an answer for you. I am sorry I can't be more helpful on this one, but you and your fish deserve an answer that can help you all :)

Customer: replied 10 years ago.
Thanks Gina.
FYI - I just went and checked the water again. Same as my previous reply. Nitrate, Nitrite and Ammonia level are all at zero.
Hi Celeste. Ric here--I work side by side with Gina here as we're part of Just Answer's Fish Team.

I'd just like to reiterate the problems you mentioned so that we're all on the same wavelength: Goldfish with damaged fins, missing scales and one goldfish floating to the surface and not moving.

Gina covered some basic issues such as water quality which you mentioned was fine as this is always the first place to look.

The treatment plan suggested by Gina, Pimafix and Melafix, was proper procedure as these two medicines are generally good starter treatments as they will not damage water quality due to the fact that they are all natural.

Celeste you wrote that you do regular water changes and that is excellent husbandry on your part and should always be continued.

What we're dealing with here is a stronger than usual bacteria as seen by the fin and scale deterioration and Swim Bladder Disorder as seen by the fish floating to the top and maintaining a stationary position. Note that some Swim Bladder Disorders are also caused by bacteria and I believe the same bacteria is causing both problems.

In a case like this I would advise that a stronger medicine be used to combat the bacterial issue. Maracyn is an ideal medicine for this situation. Listed below is a link to a page that will show you the product. Just follow the directions on the packaging label for use.

On a final note I'd like to mention two other things. Keep in mind that Goldfish are not tropical fish and an ideal temperature range for them is between 62f-72f degrees and also as Gina had stated, keep an eye out for the fish fighting as a 10 gallon tank is considered a tight fit for two goldfish.

You're doing a great job with the fish Celeste but unfortunately diseases still manifest themselves despite all of our efforts. Try the Maracyn and I think everything will work out ok.
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Customer: replied 10 years ago.
Thanks Ric & Gina! Luckily I have Maracyn at home so I will try it out tomorrow. Thanks again.
Good luck Celeste and please remember to test the water during and after treatment as Maracyn while killing off the bad bacteria will also kill off the good bacteria. The stronger medications tend to work this way.
Customer: replied 10 years ago.
Relist: I still need help.
Hi Ric - I still need help here. These days the weather becomes very warm. The temperature in my tank is 80F. The fish still act the same but I start to worry as the water is too warm (BTW, I started the Maracyn treatment, today is the second day). Is it going to cause a problem to my tank? Unfortunely I don't have a Air Conditioner. Is it neccessary for me to get a chiller for them? Last summer when it got very hot 2 of my goldfish turned from gold to silver (not sure if they changed color because of the temperature). Any ideas? Thanks Ric.
Hi Celeste. 80f degrees is much too high of a temperature for goldfish. Contrary to what many believe, goldfish are not tropical fish.

The ideal temperature range for goldfish is between 62f-72f degrees. A chiller would be ideal but is very expensive. Chillers are generally used in salt water tanks where warm water can be fatal to the inhabitants.

What you can try in an effort to keep the temperature down is place a fan in front of the aquarium and let it blow air directly on to it.

Another method is to put a bag of ice cubes in the water but this could get a little tricky as the water temperature would start to drop rather quickly and then as the ice melts would then rise somewhat quickly possibly inducing temperature change shock to the fish. I would only advise using this method during a heat wave and only if you were not going out as the temperature would have to be monitored frequently.

The high water temperature will not negate nor enhance the effectivness of Maracyn. Maracyn although, might effect the bacterial balance so after treatment is terminated I suggest you test the water on a daily basis for a few days just to make sure everything is ok with the water parameters.

As for the goldfish changing colors, goldfish generally do change colors as a result of genetics but temperature changes can and do affect fish coloration. Logically speaking I think that the temperature change is what caused the color change in the goldfish last year as the probability of both of them changing colors at the exact same time due to genetics is highly unlikely.

My point of view in this case is to not worry too much about something that we have no control over, the temperature. The best thing that you can do in these Summer months are more frequent partial water changes and closely monitor the water parameters. Also if you stop and think about it, even if you had air conditioning in the area where the tank is it would not be economically feasible to run it 24 hours a day in order to maintain a correct water temperature although I'm sure Con Edison would disagree.

Hope this information helps and please let me know if you have any questions.