Can disease in a system never show symptoms?

[reefermike1]

My tank has been running with fish in it about 3 months now. I have 4 out of 6 chromis and two clowns. Within a couple weeks one of the chromis developed a lesion on his head and died soon after, the second one just went missing one day. All remaining fish appear healthy, eat well, and I see no signs of ich or any other disease at this point or within the last 2 months.

I plan to quarentine and tank transfer every new fish I get from now on, but I'm a little weary of the current residents. How long would the common diseases like ich and velvet take to show symptoms if ever? Should I just quarentine a new fish with the tank transfer method like the thread about it reads, introduce him, and see what happens? That way if he did develop a disease then it must have been in present in the system. Right? (Looking at a Figi Foxface)

Thanks for the help.

 

[snorvich]

Difficult question. My opinion is that your tank has not been running long enough to ascertain if you have a potential for ich to be lurking. I think it has been running long enough to assume you do not have velvet or brook.

 

[reefermike1]

Thanks for the reply. In your opinion, how long should I observe before I can assume the coast is clear with ich?

 

[HumbleFish]

IMHO, a highly skilled marine aquarist can manage Ich almost indefinitely. There is a person with a 40-something year old reef tank on this board, he doesn't QT, and his tank is the perfect example of this. However, snorvich is right about velvet & brook... no managing those.

 

[triggreef]

IMO what you described sounds like Uronema Marinum. It generally only effects weak/stressed fish, so your 2 chromis that died were probably 2 that were picked on from the others. Could still be in your tank, but possible nothing happens until another of your fish get picked on enough to bring down their immune system. Are there inverts in the tank yet? If not you could try a couple doses of metro and then remove it with water changes/carbon.

 

[snorvich]

IMO what you described sounds like Uronema Marinum. It generally only effects weak/stressed fish, so your 2 chromis that died were probably 2 that were picked on from the others. Could still be in your tank, but possible nothing happens until another of your fish get picked on enough to bring down their immune system. Are there inverts in the tank yet? If not you could try a couple doses of metro and then remove it with water changes/carbon.

Could be but hopefully not. If there was brooklynella type symptoms, then it most likely was. Flagyl (metronidazole) is by far the most effective drug available against uronema marinum. Indeed it is the only effective treatment for fish that are internally infected with Uronema marinum, but it has to be administered in the diet. To treat with Flagyl (metronidazole), add 34mg/l (34mg/kg bodyweight is required if treating the internal disease) of the drug to the aquarium water to be treated. A single dose should be effective, but it can be repeated daily, if required, as the drug is well tolerated by most fish. It is a very reef safe drug having little impact on invertebrates BUT it will kill off all protozoans and anaerobic bacteria in the treated tank, so, like all medications that are used in a reef tank, it will have some undesired effects on the ecological stability of the tank.

 

[reefermike1]

I Thought the same thing during that first couple weeks and mixed metro in with daily feedings for about a week. The afflicted fish died and the other five seemed fine untill one went missing within that same week. That was before I added the clowns two or so months ago. I didnt really want to add the clowns when I did, timing just worked out that way.

I haven't seen any symptoms under daily observation for about 2 months. I would pretty much need to drain the water and pull the rock to get the fish out to qt them like I should have in the first place. I'm hesitant to do this obviously, especially since I'm not sure if there's any real need to. I've never seen any symptoms of ich on any of the fish, so my question was is there a set amount of time that if you haven't seen any symptoms you should be good?

 

[HumbleFish]

I've never seen any symptoms of ich on any of the fish, so my question was is there a set amount of time that if you haven't seen any symptoms you should be good?

Highly unlikely. Once you have ich in a tank, it's usually there until you go fallow. I've known several people (myself included) who went years without seeing symptoms and then one morning ich rears it's ugly head.

 

[snorvich]

Highly unlikely. Once you have ich in a tank, it's usually there until you go fallow. I've known several people (myself included) who went years without seeing symptoms and then one morning ich rears it's ugly head.

Unfortunately. While it can be eliminated, lack of visible signs does not mean it is gone.

 

[ca1ore]

There is a school of thought in this hobby that every tank has ich! While as an absolute statement, that is absurd (there clearly are ways to eliminate ich from your system and prevent it from getting in again), it would not surprise me if in fact most tanks actually did have ich.

It is very difficult to prove the absence of something. If you have observable symptoms of ich on your fish, then you have ich; if you have no symptoms, then maybe you don't have ich. But absent an extensive analysis of your tank water for the parasite (which none of us are going to do) it is obviously not possible to say definitively.

Were it not for a Hippo and an Achilles Tang, none of the fish in my tank would show symptoms of ich, so given my adherence to strict QT protocols, I'd assume my tank were ich free. But its not! So, if you have followed sensible QT practices, and have no observable symptoms, I think it is reasonable to assume you have an ich-free tank.

 

[HumbleFish]

Were it not for a Hippo and an Achilles Tang, none of the fish in my tank would show symptoms of ich

This is one reason I always keep a Powder Blue; my "ich canary" as someone put it. I agree it's hard to be 100% sure your tank doesn't have ich; I worry about it all the time. Even if you religiously QT all fish/corals/LR/inverts, you still have to be paranoid about things like hands going from QT to DT. Can ich survive on my hand even after I wash with soap & water? I even read somewhere that ich or velvet can be transmitted via aerosol. So, don't keep that QT too close to your DT.

 

[Deinonych]

It's too bad there isn't an easy test or assay for cryptocaryon. Would take a lot of the guesswork out of diagnosis, and prevent unnecessary treatments.

 

[HumbleFish]

It's too bad there isn't an easy test or assay for cryptocaryon. Would take a lot of the guesswork out of diagnosis, and prevent unnecessary treatments.

Not "easy" but I've wondered if putting a water sample under a scope might yield some results. Of course, you'd probably have to have a heavy infestation to collect enough free-swimmers for viewing.

 

[Deinonych]

Not "easy" but I've wondered if putting a water sample under a scope might yield some results. Of course, you'd probably have to have a heavy infestation to collect enough free-swimmers for viewing.

It's possible you might see one. Best way would to extract a relatively large volume of water and centrifuge it to precipitate the parasites for study. But, most of us don't have access to a lab-grade centrifuge.

 

[Triggerfish]

There is a school of thought in this hobby that every tank has ich! While as an absolute statement, that is absurd (there clearly are ways to eliminate ich from your system and prevent it from getting in again), it would not surprise me if in fact most tanks actually did have ich.

It is very difficult to prove the absence of something. If you have observable symptoms of ich on your fish, then you have ich; if you have no symptoms, then maybe you don't have ich. But absent an extensive analysis of your tank water for the parasite (which none of us are going to do) it is obviously not possible to say definitively.

Were it not for a Hippo and an Achilles Tang, none of the fish in my tank would show symptoms of ich, so given my adherence to strict QT protocols, I'd assume my tank were ich free. But its not! So, if you have followed sensible QT practices, and have no observable symptoms, I think it is reasonable to assume you have an ich-free tank.

And there you have it...nice summation.

 

[snorvich]

It's possible you might see one. Best way would to extract a relatively large volume of water and centrifuge it to precipitate the parasites for study. But, most of us don't have access to a lab-grade centrifuge.

Given the small percentage of the life cycle that tomites exist and their size, microscopic analysis seems problematical. Theronts of one strain were 20"“30 x 50"“70 µm (Colorni 1985), but size will vary depending upon strain, host species, and temperature. The theront's infectivity is highest early in its life. By 6"“8 hours after it leaves the cyst, its infectivity is greatly reduced (Burgess 1992; Yoshinaga and Dickerson 1994; Colorni and Burgess 1997; Dan et al. 2009), although a non-infective theront may still be able to move for up to 48 hours.

 

[reefermike1]

Highly unlikely. Once you have ich in a tank, it's usually there until you go fallow. I've known several people (myself included) who went years without seeing symptoms and then one morning ich rears it's ugly head.

Unfortunately. While it can be eliminated, lack of visible signs does not mean it is gone.

I never observed any visible signs of ich ever in this setup on any fish.

That is my question, would it be possible to have not seen symptoms yet if were present?

If it is possible, then my plan was to proceed with adding a foxface after qt using the ttm. If the new fish once in the display develops ich, then I would know ich was present and I can tear down the tank and ttm all fish while leaving the tank fallow.

If he doesn't develop ich, would it be a safe assumption that I'm ich-free?

 

[Triggerfish]

If he doesn't develop ich, would it be a safe assumption that I'm ich-free?

you could make that presumption.. but one may never know for sure.
ich strains have also been reported to eventually die off over time. some quicker than others.

 

[Deinonych]

Given the small percentage of the life cycle that tomites exist and their size, microscopic analysis seems problematical. Theronts of one strain were 20–30 x 50–70 µm (Colorni 1985), but size will vary depending upon strain, host species, and temperature. The theront's infectivity is highest early in its life. By 6–8 hours after it leaves the cyst, its infectivity is greatly reduced (Burgess 1992; Yoshinaga and Dickerson 1994; Colorni and Burgess 1997; Dan et al. 2009), although a non-infective theront may still be able to move for up to 48 hours.

Agree that microscopic analysis is problematic. Isolating the tomites/theronts would be the most difficult part. However, 20-70µm is well within the resolving power of even an inexpensive student microscope at 100x -- but only if you can isolate the organisms for examination.

 

[snorvich]

Agree that microscopic analysis is problematic. Isolating the tomites/theronts would be the most difficult part. However, 20-70µm is well within the resolving power of even an inexpensive student microscope at 100x -- but only if you can isolate the organisms for examination.

Yes, seeing it is not the issue, finding it is the issue.