Is uronema in a tank going to kill chromis

Miami Reef · Mar 19, 2022

Will having uronema in a tank (Aquabiomics testing) actually affect established and healthy chromis?

I never really believed that, but I do hear from people that say if you have uronema in a tank, you should avoid uronema prone fish.

But I feel like uronema only really affects new prone fish? Can someone clarify this?

Miami Reef · Mar 19, 2022

No, I don’t think I have uronema and I don’t own chromis.

Just interesting in learning because I read having uronema is pretty much a given when buying corals and live rocks, and I wanted to know if I could add uronema prone fish to a system that may or may not have uronema in the substrate.

MnFish1 · Mar 19, 2022

Since not a lot of tanks have had that testing done - Its probably difficult/impossible to answer

vtecintegra · Mar 20, 2022

Anything is going to be theory or personal opinion. Some say it's in every system. I doubt it. And while it's pretty deadly to Chromis, there is some level of immunity. They are in tanks with other fish at the store, and all of the others don't drop dead. And neither does every Chromis. It is the fish I would do the longest QT with.

monkeyCmonkeyDo · Mar 20, 2022

What is urnoma? Ich?
If so yes I think it's present in a lot of tanks but doesn't show
D

Jay Hemdal · Mar 20, 2022

Miami Reef said:
Will having uronema in a tank (Aquabiomics testing) actually affect established and healthy chromis?

I never really believed that, but I do hear from people that say if you have uronema in a tank, you should avoid uronema prone fish.

But I feel like uronema only really affects new prone fish? Can someone clarify this?

As they say, it's complicated. "Uronema" isn't always what we think it is. There are at least two species of Scuticociliates involved, Miamensis is one of them, Uronema is the other. Then, that is genus only, what if there are different species with different degrees of infectiveness?

The external disease, see in seahorses and seadragons does seem to be contagious fish to fish.

IMO - the internal version, seen so often in green chromis, only affects newly acquired fish (<45 days in captivity?). I have not seen that spread to older fish in the same systems.

Then there is the whole issue of non-pathogenic "Uronema". The free living form lives on bacteria. Back in the 1980's, at the Shedd Aquarium, I was diagnosing "Uronema" on a lot of fish that had died. My curator, on a hunch, said, hang a piece of smelt in the tank for 36 hours and look at that. I did, and found Uronema there in even greater numbers. Turns out the Uronema was just feeding on the bacteria growing on the dead fish. That was my curator's way of letting me find that out for myself....

Jay

AquaBiomics · Mar 20, 2022

Sometimes people say "its everywhere" but thats clearly not true. it is however the most prevalent parasite in the hobby. Uronema shows up in about 10-20% of the tanks we test.

To clarify since Jay brought up Miamiensis - we do detect several other parasitic ciliates including Miamiensis but they are genetically different enough that they are identified as such.

We also see a close relative of U. marinum sometimes, U. heteromarinum. This thing is morphologically almost identical to U. marinum, and shows up at a similar prevalence (~10% of tanks). Although it hasnt been published as a parasite yet, since its almost impossible to tell them apart I suspect its also playing a role in the disease we see in the hobby.

For your actual question - will it kill Chromis if you add them to the tank?

This is very hard to say since Chromis are in my experience the absolute shortest lived, most sensitive, most likely to die cause you looked at them funny, fish in the entire hobby. I will cynically say: if you add a Chromis to your tank its likely to die, but I'd say the same thing regardless of any test results.

But I do think that these populations of parasites - including Uronema - contribute to deaths of newly introduced fish. When a tank of mine shows up with Uronema, I don't add any more fish til its clean.

Miami Reef · Mar 20, 2022

AquaBiomics said:
But I do think that these populations of parasites - including Uronema - contribute to deaths of newly introduced fish. When a tank of mine shows up with Uronema, I don't add any more fish til its clean.

And how do you clean a tank of uronema? Especially when you are adding live corals/rocks to it?

Here’s my beliefs and opinions based on what I’ve read:

Keep a clean, low detritus tank.
Introduce copepods (they can eat uronema)
Quarantine all fish.

I believe uronema prone fish can live in this environment. This is my opinion of course.

AquaBiomics · Mar 20, 2022

Miami Reef said:
And how do you clean a tank of uronema? Especially when you are adding live corals/rocks to it?

Here’s my beliefs and opinions based on what I’ve read:

Keep a clean, low detritus tank.
Introduce copepods (they can eat uronema)
Quarantine all fish.

I believe uronema prone fish can live in this environment. This is my opinion of course.

I agree that cleaning up detritus is a good idea when trying to rid a tank of ciliates. I havent tested detritus for Uronema specifically but its certainly full of ciliates in general.

I was intrigued by published studies of copepods eating Uronema so we did some experiments. Unfortunately we didnt find any positive results - Uronema persisted after a month with high levels of copepods. But a single failed experiment (even replicated, like ours) isnt proof it doesnt work. The details of these treatments often matter a lot... we've found one way that doesnt work, but others might. I would love to see some positive results in this area, I'm a big fan of biological control in the aquarium.

What does seem to work is peroxide treatment. Several clients have tested before and after the treatment and showed removal of Uronema. Many others have confirmed Uronema's absence after peroxide treatment. And in our own experiments, it looks like an effective way of cleaning up infected live rock (without killing the microbes).

Since I'm not at all an expert on the treatment itself, I'll refer the reader to descriptions on the Humble.fish forum - there may be descriptions here too, I've been off forums for a while so I may have missed some discussions about it.