10 Gallon Tank Goldfish mole

My Goldfish has developed what looks like a mole. It seems totally fine otherwise. It also has two darker, more faded, spots on its tail fin. Both have suddenly appeared and have been there for months now. What are they? Probably not ammonia poisoning because the spots have not worsened or lessened over these past months and ammonia levels are fine. The “mole” near its dorsal fin also seem to have very sharp outlines which would not be the case with ammonia burns. A probably unrelated note: last time when I did a water change tiny bubbles of air seemed to attach themselves to a very thin and translucent string attached to the goldfish body. It may have been nothing and i cannot see it now. As a precaution I have dosed him with ESHA 2000. That did nothing for the dark spots. Any ideas? A natural change in color or a sign of some sort of disease ?? Thanks in advance for your ideas, folks.

 

Is the tank cycled? Is the 10 gallon tank label correct? Goldfish need at least a 29 gallon tank. And that looks like the type that gets huge, that kind needs 55g or more

 

If you didn’t cycle the tank that’s a common cause for most fish illnesses. And like FishGirl115 said that goldfish gets huge. It looks like a comet to me and those need a pond. Maybe the black spots could be tumors? Or skin flukes (I have no idea what those look like)

 

Yeah, honestly that mole thing doesn’t look like a problem it might be ammonia burns or a tumor though. Did you research at all?

 

Is the tank cycled? Is the 10 gallon tank label correct? Goldfish need at least a 29 gallon tank. And that looks like the type that gets huge, that kind needs 55g or more

I agree with fishgirl! That looks like a comet goldfish, a species which can sometimes grow up to 2 feet. That 10g will not hold it at all, as even at its current size, it is probably producing a very large amount of ammonia.

Comets need a 75+ gallon tank for only one fish!

What are the water parameters?

 

I’ve had something happen on some of my goldfish before where just a single scale will change color. There are multiple factors that can cause it, such as being in a small tank or a sudden change of conditions. It doesn’t seem harmful. I had a comet much like this one that was almost all black, and one single scale on top of its body turned white. I got scared and thought it was ich at first, but it was just a scale. Maybe this is what happened to yours.

 

I don’t think the mole is an issue. The tanksize though, that could be. I would upgrade or rehome. goldfish are really hardy so I wouldn’t worry about the mole, my goldfish lost an entire eye and it’s ok so far.

 

Thanks for all your replies. To be polite I will respond to some of the questions I have received, in random order.
1. I also don’t think it’s something to worry about, as the fish itself seems to be thriving. I will just keep an eye on it but I am curious as to what it might be. It is not a brown colored scale. It has a different shape (oval) and is smaller.
2. I agree with all of you that the tank is too small. However it is a solitary goldfish (that used to have a tank mate, but said tank mate has been sickly from the start and although I kept it alive for about three years it didn’t grow much, became lethargic and eventually died, while the other goldfish - this one; Piet - thrived and actually grew to be around 20 cm in that amount of time). I perform weekly water changes and will upgrade the tank sometime in the future when it (actually it’s my daughter’s fish) becomes too large for its current tank. At that time I will also introduce a new tank mate.
3. The tank is cycled and monitored with test strips. All values are within the parameters which are recommended in the instructions that came with the strips.
4. Gill flukes - doesn’t look like it. I did see a thin translucent string trailing from his body the other day, so I figured the “mole” could actually be the spot where a parasite (anchor worms? -however they should be visible more readily) attaches itself to the goldfish. As a precaution I started treatment with Esha 2000, to no effect.
Thanks again for all of your replies, if anyone has a different idea as to what the mole might actually be, I’d be happy to hear it.

 

I did see a thin translucent string trailing from his body the other day, so I figured the “mole” could actually be the spot where a parasite (anchor worms? -however they should be visible more readily) attaches itself to the goldfish.

Usually translucent strands of poop are a sign of internal parasites. Anchor worms, ich, Gill flukes, and lots of others are external parasites and don’t usually cause the strands. This is just what it’s been like in my experience, it might be different for others. Also, good for you for wanting to upgrade the tank!

 

Thanks Kribensis. No translucent poop. Only solid brown turds which I have to clean up every week. With my stupid vacuuming tool that has a plastic valve which gets stuck in the open position constantly, only to be brought back to life with a drinking straw inserted from the bottom so it closes properly... ugh

 

Thanks Kribensis. No translucent poop. Only solid brown turds which I have to clean up every week. With my stupid vacuuming tool that has a plastic valve which gets stuck in the open position constantly, only to be brought back to life with a drinking straw inserted from the bottom so it closes properly... ugh

Happened to me too.