Why Does My Goldfish Have a Bump?

[mawgui]

One of the goldfish has had a tough time recently.  He has been losing color.  This guy was originally all silver but turned gold when I changed the goldfish food.  That is okay I think.  A couple months ago he had a minor case of dropsy (pine cone appearance just starting to develop) but I treated him promptly, following advice from this site from a year ago.  It worked and he recovered!  (Hallelujah!)   

He now has a bump on his side, which is clearly evident on the photos.  I did not see it arise.  It does not seem to have gotten bigger in the past week.  He is an active swimmer and eats fine (although he seems to sometimes bump into food rather than eat it).  I have three goldfish in a 20 gallon tank - one of which has grown like topsy and is three times his size  The tank is cleaned weekly and 50% of the water replaced.  The water tests fine.  There are no plants in the tank and no fish have been introduced into the tank for a couple years.

What is this bump?  Will it go away?  Do I need to do something to make it better?  Thank you!

 

[FishyMandy]

Hi, its a bit hard to see in the photos, but it looks like a tumor,

Unfortunately,  short of surgically removing it, there isnt really anything you can do.

But ive had fish who have lived happily with tumors for at least a few years

[koko]

On 12/5/2020 at 1:02 AM, FishyMandy said:

Hi, its a bit hard to see in the photos, but it looks like a tumor,

Unfortunately,  short of surgically removing it, there isnt really anything you can do.

But ive had fish who have lived happily with tumors for at least a few years

I agree that does look like a tumor. :O 

[mawgui]

It's been awhile but I need to post an "epilogue" to my earlier question. 

My "goldfish" has become entirely silver.  She has recovered entirely, with just a slowly re-scaling spot as a memento of her misadventure.

[spider man]

color change is not unusual as fish age and mature. That is quite normal  so long as your water conditions are excellent. I would do  a much larger water change than 50% as your tank is very over stocked.  At minimum I would do at least 2 , 50% water changes or 1, 85% water change per week using Prime as my water conditioner.

As far as the bump, does it feel soft or hard to the touch. Sometimes when the fish looses scales, there can be some growth like that that is not tumor related. Please feel the fish and see if the bump is hard or soft.

[mawgui]

Thanks for your note. The fish was actually silver to start with, then turned gold because the pellets had a color enhancing additive or something.   As I mentioned, the bump is gone and the scales are regrowing.  He actually seems pretty happy.  Thanks again.  

[koko]

On 11/22/2021 at 8:06 PM, mawgui said:

Thanks for your note. The fish was actually silver to start with, then turned gold because the pellets had a color enhancing additive or something.   As I mentioned, the bump is gone and the scales are regrowing.  He actually seems pretty happy.  Thanks again.  

Thats great new! 👏