It’s time for an update on my sick goldfish and what I found out from the University of Florida Aquaculture lab regarding a diagnosis for them.
If you’re not familiar with the situation here’s a quick recap of what happened. It all started in May, which means I’ve been dealing with this now for 6 months (half a year!) which is insane. In May I noticed that some of my goldfish were looking very sick. The main symptom was severe dropsy that affected multiple fish at once. Dropsy is actually fairly common in goldfish, but many people seem to agree it’s actually quite rare to have a widespread outbreak of contagious dropsy, so being that this looked highly contagious, I was concerned. Dropsy is not in itself a disease; it’s a symptom of any number of different diseases. Dropsy is when you see the scales lift up in a pinecone-like appearance and it indicates an excess of fluid being retained by the fish’s body and this fluid retention is usually caused by the kidneys not working properly. Kidneys can fail to function because of bacteria, parasites, viruses, poor water quality, and other things like polycystic kidney disease. Because dropsy can have so many different underlying causes, it is extremely difficult (if not impossible, I think) to treat. But, it really depends upon what the underlying cause of the dropsy is and if you can detect it early enough to treat it effectively. I settled on a schedule of medications that actually seemed like they might have been helping at first.
After a few really touch-and-go months of treating and observing my fish, I started to actually feel somewhat optimistic that the treatment had worked and my remaining fish were going to be okay. At this point, I had lost about half of the fish that I had at the start. But not long after I started to feel hopeful, multiple more fish developed new dropsy symptoms literally overnight. So it became clear that the original problem was still present. At this point, I also had to be very careful about using any further medications because medications of any kind put a strain on the kidneys, which were already compromised from the beginning (as evidenced by the dropsy). So I decided it was time for a more serious approach and I reached out to the University of Florida Aquaculture lab for help with getting a definitive diagnosis.
The lab needed me to send at least 4 fish that would be euthanized upon arrival and dissected for careful microscopic inspection of the internal organs. I selected the 4 sickest looking fish in hopes that I could save the rest of them by doing this.
Right away the lab reported quite a bit of excess fluid buildup inside the body cavities of all the fish, which pointed to the kidneys not working properly, but that alone could have a number of different underlying causes (as we know). So they ran a ton of different bacterial cultures, looking for everything from the more “run-of-the-mill” type of bacterial infections that aquarium fish commonly get up to the more serious and even incurable bacteria such as mycobacteria. But in the end, they were able to rule out a bacterial cause of the dropsy because all the bacterial cultures were negative.
They then inspected the internal organs of the fish, which is called Histology. It’s pretty interesting how they‘re able to do this; the organs had to be preserved and sliced into microscopically thin slices by a special machine that slices them only a couple microns thick. It was a wait of 48 days, all told, to get the final results back.
Unsurprisingly, since dropsy was the main symptom that the fish were showing, the lab found severe damage to the kidneys in all the fish that I sent for workup. They found many granulomas in both the anterior and posterior kidneys of all fish. These granulomas were an immune response of the body trying to wall off something it didn’t like, such as a bacteria, parasite, or foreign body. Since they had already ruled out bacteria, it was looking like it was probably a parasite. On the posterior kidney, which is responsible for filtering the blood, they also found many calcified tubules, which is another sign of severe damage to the tissues.
Even though they found severe tissue damage to the kidneys, they couldn’t pinpoint a definitive cause. On the slides, they were able to clearly see all the different ways in which the kidney tissues were damaged, but they did not see any parasites. It doesn’t mean that the parasites weren’t there, it just could mean that they weren’t present in that particular slice of tissue, which is not uncommon. Since the tissue slices that are used in histopathology are so incredibly thin, they really can only look at a tiny portion of the entire kidney. Which means that the parasites could have been (and probably were, I think) present in the kidneys, but they just didn’t happen to get any in the slices they took for observation.
Even though the lab couldn’t give a definitive diagnosis, they felt that the findings could point to one of two more likely parasitic candidates – and these are either Ameoba or a very tiny myxoxoan type of parasite called hafferellis. Both have been cited in scientific literature as being able to cause the particular type of kidney damage that was found in my fish. So it’s very possible, although unfortunately not 100% confirmed that this is the parasite at play here. The terrible thing is that neither of these parasites have any known treatment, so they’re incurable.
Even if I had wanted to put my fish through some experimental treatments hoping that something would work against these parasites, I couldn’t because the parasites had damaged the kidneys so badly that treating my fish with even the most gentle of medications could put them over the edge and kill them instantly.
So at this point I’ve exhausted every possible avenue to try and help my fish, even up to spending hundreds of dollars on these lab tests. The lab results pointed to an incurable and highly contagious parasite and experimental medications were not an option due to how damaged their kidneys already were. More of my fish had already died with dropsy just while waiting for lab results to come back, and all of my remaining 12 fish were very lethargic and showing signs of dropsy as well. I really hate that this was the only option left but in the end, I had to make the decision to euthanize the remaining fish and end their suffering.
This is a really weird time for me, because I have no goldfish and I haven’t been without goldfish in 9 years. I don’t even feel 100% like myself and it seems like a part of me is missing. I will get goldfish again, but it’s going to be a little while until my aquariums are ready for new fish, so now we wait I guess.