Unknown disease causing new fish mortality - best course of action?

[Pat Niemeyer]

I have an 8 year established tank that currently has only one fish (a coral beauty) and some inverts/coral. I am about at the end of my rope and thinking of giving up my tank because for the past year or two every new fish I've put in my tank has gone through the same cycle: It's fine, eating, etc. for between 3 days and a week and then it turns up dead... Sometimes they "pant" in the corner for a day, sometimes they just disappear overnight.

I believe I have eliminated every possibility other than disease... The CB, coral, and inverts are all doing fine. It's only new fish (any kind) that seem to quickly die. I even went through (the hell) of removing rocks to capture the CB and put him in the sump, thinking that he might be killing the fish at night.

The latest fatality - a clown fish - started hanging in the corner and when he died I quickly removed him and examined him. I looked at his gills, etc. but I couldn't see anything that looked obviously wrong to me. I froze him, in case some LFS might be able to see something.

So my question is - not having any idea what is killing my fish - Where do I start to resolve this?

If I get rid of the coral beauty and wait 12 weeks will that eliminate most parasites / diseases or only certain types? Should I treat the tank with something? (keep in mind that I have coral).

Should I just scrap the tank, bleach it, and start over?


Pat

 

[RBU1]

Interesting...

How is the oxygen level? Do you have good areas were a pump is breaking the surface? What is your PH reading?

Could be a prasite but I would think you would have seen something on at least a few of the fish you lost.

 

[Pat Niemeyer]

Interesting...

How is the oxygen level? Do you have good areas were a pump is breaking the surface? What is your PH reading?

Could be a prasite but I would think you would have seen something on at least a few of the fish you lost.

It's a 90g Oceanic tech series tank with a wide overflow, sump, and skimmer... So I don't think it's an O2 problem. pH is normally 8.2... I do have a lot of algae at the moment, but as I said, in general the coral, inverts, and my singular fish are doing fine. It's just new fish that die within a week. I'm convinced at this point that it's a disease phenomenon.

 

[Pat Niemeyer]

Just as a followup - I have never seen on any of the fish any signs like white spots or obvious parasites or lesions. I have seen frayed fins, although I have not seen them scratching against rocks. The only pattern is: fine for a few days to a week, then reclusive or struggling, then dead within a day or two.

This has happened over and over again... I've gone through maybe a dozen (poor) fish over the past year or two in an attempt to repopulate my tank.

 

[wooden_reefer]

It's fine, eating, etc. for between 3 days and a week and then it turns up dead... Sometimes they "pant" in the corner for a day, sometimes they just disappear overnight.



Pat

What do you mean by 3 days or a week? Did they all die while in QT tank?

Do you have UV in both QT and DT? What wattage and at what flow rate?

It is quite possible that the CB has acquired immunity to a certain rather virulent pathogenic bacteria.

UV when used properly will drastically reduce waterborne pathogen concentration; this can well permit a fish to acquire antibodies with very limited exposure. Fish has white blood cells as general defense without prior exposure.

 

[Pat Niemeyer]

I have never had a QT tank... which probably explains how I acquired the problem.

All fish were fine / eating for between 3 days and a week or two... then all died rapidly.

 

[wooden_reefer]

Also, have you been shopping from the same LFS?

It is also possible that the same LFS that frequently obtains fish from the same small circle of suppliers can get inferior livestock.

 

[Pat Niemeyer]

This has happened with fish from 3 different LFS over the span of the past year or two. I'm really thinking that my tank is harboring a disease of some kind. Not sure how to proceed short of starting over.

 

[Pat Niemeyer]

Hi-res pictures of dead fish... see anything?

Hi-res pictures of dead fish... see anything?

My last fish died on April 8th and I took these detailed photos of his corpse that day:

http://pat.net/misc/deadfish/deadfish1.png

In this one I pried open his gill (ug) but it seemed healthy to me:

http://pat.net/misc/deadfish/deadfish2.png

I was hoping someone might see a parasite or some sign of disease. I don't see any outward signs of illness... but every new fish that I had introduced over the past year died within a couple of weeks... so something was killing them.

I have let the tank go "fallow" for two months now (no fish, just the existing inverts and coral) and I'm planning to let it go for perhaps another month before trying again. Does 3 months sound like a reasonable time period to let whatever is in there cycle out and die? If it happens again I'm just going to tear down the tank and give up...


thanks,
Pat

 

[NyReefNoob]

pat ive been going through the same thing myself, all levels are good, temp stays consistant ect, lost all but 4 of my fish and even after having waited to put anything new in i finally added 1 and 4 days later it dropped too

 

[LisaD]

All I can think of to suggest is to set up a QT and see how the fish do.

If fish do okay in QT (and you make sure you don't contaminate from your tank) then the problem is your tank.

I have kept seahorses where one species appears very healthy, but is most likely a symptomless carrier of a disease which wiped out other species. This has been observed with seahorses in other tanks. I haven't heard of it with other fish, but maybe your CB is a "typhoid Mary".

 

[GACDIVER]

Dead fish tell no tales. Unless you see obvious external dammage you should do a slide scraping of the side (pec fin area) and caudal peduncle. Examination with a microscope would yeild anything if there. A necropsy would then be the next course of action to ascertain organ functionalaty.

I also agree that a UV sized correctly is the best defense.

The symptoms that you describe remindes me of a persistant monogean gill parisite.

Sean