Sick Green Chromis

[peterac]

I recently completed cycling my 450g marine tank. Water is as follows: Amm=0, NH2=0, Nitrates=20, pH=8.0, Alk=300, sg=1.024.

I added 7 Green Chromis and one Yellow Tang. The other day I noticed one of the Chromis started showing an area of lighter color (as if the Green was bleached away. The area got larger over the next day and then I started to notice within the lighter area there was a darker area (more like the looks of a wound). He then died quickly. The others looked okay with the exception of one of them and the same pattern happened quickly to him and he just died.
Now one of the Chromis has 2 lighter area on his tail and I am assuming he is next.

The Tang looks fine and the rest of the Chromis look good. I can't tell if this is a parasite or not.

Any ideas?

Thanks,
Pete R.

 

[steve-s]

Sounds like it could possibley be Uronema. Chromis are commonly prone to it. Often if not very advanced, it can be treated sometimes with a QT stint and a treatment of nitrofurazone @ 30mg/gal (one time dose) for five days. If a bit more advanced, formalin baths and quarantine are usually needed. Just be sure not to use formalin if there are any red areas/sores showing.

Cheers
Steve

 

[peterac]

My lfs said that this sounds like a problem that they are aware of specific to the Chromies. The person I spoke to said they did not know of a specific pathogen, however. She said that it would probably not affect my Yellow Tang.

Does anyone know of parasites that are selective for particular fish and do not spread non-specifically?

Thanks,
Pete R.

 

[steve-s]

As I already said, Uronema marina is quite common to chromis specifically but there is no such thing as a species only parasite. Any parasite will eventually infest all fish within a system no matter which fish it starts with. In that regard your LFS is completely wrong.

Cheers
Steve

 

[peterac]

If my other Chromis survive and I assume this was Uronema will I be okay moving forward. Or is it stubborn like Ich and I need to allow the tank to go fallow.

 

[steve-s]

The life cycle of Uronema is not well understood so it's hard to say. From a purely precatious standpoint, it would be best to leave the tank fallow for a minimum of 3 weeks. It is not nearly as long lived as C. irritans AFAIK.

Cheers
Steve

 

[peterac]

Thanks Steve. However, as you can see from another thread I am having major problems capturing the fish. This is the largest tank I ever dealt with. If the suspected Uronema does not affect any more fish for say another month, do you think I am still putting future additions to the tank at risk? In other words, do you think the parasite can stay dormant and not affect the current livestock and suddenly become active in a month or longer?

Moving forward I will ABSOLUTELY QT all new arrivals (and possible do preventive dips as well).

 

[steve-s]

If the suspected Uronema does not affect any more fish for say another month, do you think I am still putting future additions to the tank at risk? In other words, do you think the parasite can stay dormant and not affect the current livestock and suddenly become active in a month or longer?

If it is Uronema it will most likely kill the remaining fish in time. I would not add any more fish until these have been removed for treatment or the unfortunate alternative occurs. Then the tank should be fallowed for 3-4 weeks to be safe. Any fish added at this point would be at risk as long as the chromis remain. As I said the life cycle is not very well understood so I am unsure if it's possible for the problem to "burn itself out" so to speak. From what I understand, it is usually always fatal if left untreated.

Moving forward I will ABSOLUTELY QT all new arrivals (and possible do preventive dips as well).

QT definately but dips are not necessary. It's pretty hit and miss to their effectiveness and quite stressful. As long as the QT period is no less than 4 weeks and any treaments needed are performed correctly, your good with just that.

Cheers
Steve