Jay what causes it?
Also why does it seem so pervasive if it isn't really that infectious?
There seems to be at least two types of "Uronema" - external and internal. External is seen in seahorses and seadragons, and responds to formalin and some other treatments. Those lesions start on the outside of the fish. The internal "Uronema" is a protozoan that gets inside the fish (I don't know how) and begins to consume the muscle tissue. Eventually, the lesion breaks through the skin, making it seem external, but it has actually be growing internally for quite some time. There may even be other species of protozoan involved. In general, these are all Scuticociliates, I can't tell them apart, and many species are free-living and feed on bacteria and organic matter.
The species type and collection/transport factors all seem to play a role in its transmission. The commonly affected fish are; green chromis, yellow coris, Anthias and sometimes butterflyfish. They almost always show infection in the first 40 days following importation - that implies something happening in the supply chain. Additionally, during Covid, when the supply chain was so disrupted, Uronema seemed even more common.
Somebody shared a video with me of a veterinarian injecting a clownfish with metronidazole as a treatment. Trouble is, I don't have anything more than that to go on, and to be honest, I question the diagnosis, as I've never seen internal "Uronema" in a clownfish.
I wish I had the time/resources to study this further, there is so much I don't know about it!
Jay
