JanS

This is worth reiterating, especially coming from an expert in the medical profession.

If you do regular tank maintenance and water changes, it should not be a common thing.....

dwalstad

I'm talking about all the many fish chronically infected with MB that hobbyists buy and that die a few weeks or months later. This is way too common in the hobby. MB infected fish can also introduce infection into an undiseased tank (happened to me and its described on the Rainbowfish Study Group link). Water changes or good maintenance will only slow disease progression in the infected fish.

As to autopsies, the presence of granulomas containing acid-fast bacteria are enough to diagnose chronic MB. Culturing and DNA testing is not necessary, and surprisingly, has been shown to be misleading in some instances. Chronically infected fish have granulomas that you can see visually on the organs. See the bumps on the spleen of this MB-infected Betta (NCSU Vet School in Raleigh NC generously provided it to me). Nocardia bacteria and some parasites cause similar granulomas, so acid-fast staining is necessary to "nail it".

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BryceM

It's a frustrating disease - slow to develop, sometimes active in a host, sometimes dormant, relatively low-virulent, meaning healthy fish only occasionally "catch it". Even infected fish can take months to show symptoms. Unfortunately, the most frustrating aspect is that there isn't anything that you can do to treat it.

If you can't treat it, can't accurately diagnose it without an autopsy, and it takes infected fish months to show symptoms, it really doesn't do any good to know if your fish have it or not. About the only effective measures are to buy from reliable sources - local breeders are probably the best, and to remove seemingly affected fish immediately.

Even using a quarantine tank isn't likely to help. Nobody is willing to QT fish for the several months it would take to see if it develops.

bigtroutz

Thanks for posting the photo; that helps alot. Also for the info on the particular staining technique used, not that I am likely to use it, lol.

Just gives me the willies thinking about it; pardon me while I go wash up

dwalstad

[quote=guaiac_boy;282245] If you can't treat it, can't accurately diagnose it without an autopsy, and it takes infected fish months to show symptoms, it really doesn't do any good to know if your fish have it or not. QUOTE]

You're probably right for many hobbyists, but for me the autopsies were invaluable.

The first two autopsies ($35) told me what was actually wrong with my fish. After all, I didn't know; it could have been something easily treatable. The fact that it was untreatable MB was, of course, a major bummer.

However, now I knew what the problem was--- bacterial disease. I used UV sterilizers to decontaminate the water and stop water-borne transmission of the pathogen from infected fish to the uninfected. Surpisingly (to me) my fish started to improve; even one with a sore healed up.

The next four autopsies ($135 total) done last year showed no MB in four fish (no granulomas, no nothing!). It convinced me that MB was no longer active in my tanks. I could relax.

Was it worth it? For me, it was.

littleguy

Well this is all very interesting and a bit alarming. But ultimately what is the take home message for me as a regular hobbyist?

For example, I recently bought some dwarf coral platies at a big box chain retailer. They've been in a plant growout tank for the past 3-4 weeks (a Q-tank of sorts). One of the four died within 48 hours of unknown causes, but the rest are very active, energetic, always looking for food, voraciously eating in the morning etc. But I notice their bellies are quite plump. I've never had platies before, so I don't know if they're just little piggies (they are young fish, still growing I think) or if they have a legitimate disease. In the last few days I think I can see some blood vessels on their undersides - but then again they are orange fish and maybe I'm being paranoid.

So I read this interesting thread but am left wondering what I should do. For example, I could:

1. Immediately destroy the fish ("better safe than sorry").
2. Wait it out, delaying putting them in the display tank ("wait and see"). After a few months if they still look good, put them in the display tank.
3. Just keep with my original plan and put them in the display tank as soon as it's ready to go ("business as usual"). If I discover they're sick down the road, deal with it then.

What compounds the discussion is that, if indeed the fish are sick:

• Will I need to tear down the tank that the sick fish were in? If so, then I would be extremely apprehensive about putting them in the display tank until I was 99.9% sure they were healthy. I would absolutely hate to have tear down and sterilize my display tank that took so long to set up.
• Will the plants in the growout tank (the current q-tank) be "infected" and unusable?
• Will I have to assume that every other fish in that tank is infected?
• Will I have to destroy any snails or other fish that were in the q-tank with the sick fish?
• What about any offspring of suspect fish? Are they automatically infected as well? Or can I remove the offspring to a different tank and consider them to be "clear and free" of the disease?
• Will the mycobacteria survive in a tank without fish? For example, if a q-tank once housed fish with MB, would I have to sterilize that tank before using it again, or could I just let it go for a week or a month without fish and let it naturally "sterilize"?
• Are all my tools & nets infected?

Sorry to be a pain, but in the end I seem to have more questions than answers.

BryceM

Steilizing a tank is a hopeless concept - and entirely unnecessary. MB is NOT a ravenous plague. It is a low-virulent organism meaning healthy fish have very little chance of getting it. ALL of your fish have probably been exposed to it already in their lives, especially if obtained from commercial sources. There's a good chance that some of your fish are innactive "carriers" right now. The best (and only) defense against it is a healthy aquarium with carefull attention to the little fish-keeping details that we've known about for decades.

Platties are normally pretty plump - very plump compared to most fish, even the livebearers. If they're acting healthy, eating normally, and they all have the same overall appearance I'd proceed as usual, pretending that you hadn't seen any of this. If one of them is significatly bloated compared to it's brothers, looks unhealthy, and doesn't act "right" then do whatever you think is best - personally I'd dispose of it. There's very little chance they're all equally "infected" exhibiting exactly identical signs of "bloating."

I mean no offense to anyone here, but honestly people, let's be rational about this. People are now in a panic, thinking of exterminating perfectly healthy fish due to something that has been blown way out of proportion. This is not a "new" disease. It's been around for thousands of years. We probably haven't always recognized it in the past yet somehow we've managed to keep our little critters alive and enjoy the hobby. Does it kill fish? Yes. Can it wreak havoc in your tank? Yes. Is there anything you can do about it? No. Does it spread from fish to fish to wipe out a whole aquarium? Probably not, unelss the fish are already stressed. Rant over.

Honestly, DW's best point regarding MB is that those of us who have lost fish to it (including me) have no reason to feel guilty about it. They come sick, they develop symptoms despite our best efforts, they die, we move on. In a tank of 40+ fish I saw MB develop in three zebra danios and one neon tetra. This was over a year ago. The remaining 36 fish are still healthy, still acting normally, and still showing spawning behavior.

JanS

Well said. That has been my biggest concern with this whole thread and it would be terrible to have people getting rid of fish because it has just created a wave reaction of panic.

I'm not saying that the original article isn't well written and doesn't have some very helpful information in it - it does , but not every fish ailment boils down to MB being the cause, so we need to look at the full spectrum when it comes to keeping our fish happy and healthy.
As Diana stated, all fish ailments can be extremely difficult to diagnose without the use of lab equipment and trained medical professionals, which is why I very seldom even recommend medicating unless you're absolutely positive of what you're dealing with.

BTW Littleguy, you're not being a pain at all and ask some very legitimate questions.

SKSuser

I'm speaking as one of the "panic stricken fish flushers." Tee hee.

I don't think you have to worry about us mass-euthanizing our fish. Diana's points just offer a possible explanation of why fish go along for several months after purchase and then decline and die in a tank that is properly maintaned.

dwalstad

No problem. Guaiac is right that there's no need to panic. I am sure that many fish with MB have passed through my tanks over the 50 years I've been keeping fish. They died soon after purchase, and I didn't think too much about it. In some ways, ignorance is bliss.

Bottom line: Do your quarantine as long as possible. Euthanize fish that are showing clear signs of distress. Its the smart and humane thing to do. Even if these platies do have MB, I would not assume that they will infect other fish. In the rare event that things go from bad to worse, you can always do what I did-- add a UV sterilizer to the tank. I believe this is a more effective route than tearing down tanks and chloroxing them.

Your questions tell me that you are a very careful, conscientious hobbyist. Already you've gone to the trouble to quarantine your new fish.

Quarantining new fish for 2-3 months is worth the trouble. It may not always be full-proof, but it will greatly reduce the chances of disease problems. Moreover, if the platies still look healthy after 3 months, any possible pathogen they might be carrying is probably not very virulent; it may not be able to infect healthy, well-cared for fish.

MB is just one of many (and probably not the worst) diseases that can be brought in by adding new fish directly to established tanks.