Bulge and dark shadow in gills on yellow clown goby

[Arkardios]

So my yellow clown goby's got a bulge on one side, on his gills. Taking a closer look I think I can see a shadow in there too. Is a parasite possible? Or a tumor?

 

[vetteguy53081]

So my yellow clown goby's got a bulge on one side, on his gills. Taking a closer look I think I can see a shadow in there too. Is a parasite possible? Or a tumor?

Is this fish eating? Often when this is seen there is weight loss not significantly showing followed by edema in which fish stops eating and feeds off its liver

 

[Jay Hemdal]

So my yellow clown goby's got a bulge on one side, on his gills. Taking a closer look I think I can see a shadow in there too. Is a parasite possible? Or a tumor?

In addition to if the fish is still eating, how long have you had it? How long has it had this swelling? Did the swelling show up suddenly, or did it grow over time?

 

[Arkardios]

Is this fish eating? Often when this is seen there is weight loss not significantly showing followed by edema in which fish stops eating and feeds off its liver

It is eating very well. Not picky either.

how long have you had it? How long has it had this swelling? Did the swelling show up suddenly, or did it grow over time?

Had it for about 6 months now. It was a pretty sudden onset, about two weeks ago. Doesn't seem to be getting bigger either, so far at least.

 

[Jay Hemdal]

It is eating very well. Not picky either.


Had it for about 6 months now. It was a pretty sudden onset, about two weeks ago. Doesn't seem to be getting bigger either, so far at least.

Ok, I’m trying to rule out one cause of gill swelling, thyroid hyperplasia/goiter. I think we can rule that out due to the sudden onset. However, that doesn’t leave me with a clear diagnosis…..

 

[Arkardios]

Well, there's been no change over the last months. The lump hasn't grown or receded any as far as I can tell. He's been uninterested in any food today though, which is definitely out of character.

 

[Jay Hemdal]

Well, there's been no change over the last months. The lump hasn't grown or receded any as far as I can tell. He's been uninterested in any food today though, which is definitely out of character.

Lack of appetite is not a good sign. Can you capture it for a five minute freshwater dip? I doubt that it is a parasite, but that’s really the only thing to try at this point.

 

[Arkardios]

Just went to feed the tank, and he's interested in eating but spitting everything back out. Also seems like his sides are bulging a bit...

Lack of appetite is not a good sign. Can you capture it for a five minute freshwater dip? I doubt that it is a parasite, but that’s really the only thing to try at this point.

I can definitely try.

 

[Jay Hemdal]

Just went to feed the tank, and he's interested in eating but spitting everything back out. Also seems like his sides are bulging a bit...



I can definitely try.

This video was really clear - I think that this is indeed thyroid hyperplasia, goiter. The "fast onset" may just have been that the early symptoms were easily missed on such a small fish. There isn't any treatment for this in a fish that isn't eating. For larger fish like sharks that develop goiter, you can dose potassium iodide in the food. Adding iodine to the water just never seems to work, sorry.

 

[Arkardios]

There isn't any treatment for this in a fish that isn't eating. For larger fish like sharks that develop goiter, you can dose potassium iodide in the food. Adding iodine to the water just never seems to work, sorry.

Yeah, I do have some potassium iodide in the house, and he really wants to eat, but if he can't swallow then that's that.

 

[Arkardios]

Found him lying on his side today, breathing heavy. I decided to remove him from the tank and euthanise, and found a parasitic isopod in his gills where the bulge and dark spot were.



He was the only fish in the tank at the moment, but I had planned to add a tailspot blenny in the near future. Is there a risk to newcomers?

 

[Jay Hemdal]

Found him lying on his side today, breathing heavy. I decided to remove him from the tank and euthanise, and found a parasitic isopod in his gills where the bulge and dark spot were.



He was the only fish in the tank at the moment, but I had planned to add a tailspot blenny in the near future. Is there a risk to newcomers?

That's a gill isopod, Cymothoa sp. I've never seen one on a small goby before. Was there one on the other side as well? These are not really treatable without using very strong drugs like Trichlorfon (which is also toxic to people). Sorry - if it had been a larger fish, I would have mentioned that as a differential diagnosis, but obviously, they can infect small gobies as well.