Disinfecting a hospital tank / qt after medicating sick fish

[Johanna]

Hi, I have a new question again... I want to clean my hospital tank and quarantine after the sick discus. Just not sure how I should go about it and if it is really worth the effort.

What's the best method of disinfecting an empty tank and equipment after treating sick fish? I've seen posts about people using PP and I read some articles about it in the SD library but I think it's not very easy to get here (at least in small amounts) and it's quite expensive (~50-60€/1kg) so I'm looking for alternatives.

I'm planning to throw away all filter materials and disinfect everything else including buckets, nets, heaters, filters... The problem is, I don't know what exactly caused the problems in my problem fish, if the disease was bacterial, viral or parasites. So how do I make sure that the cleaning actually kills the pathogen? I did open up the sick discus after putting him out of his misery, mostly just looking for signs of tuberculosis. Didn't find anything visibly wrong (except maybe that all the organs seemed very small compared to his size), but I'm not an expert... I didn't microscope anything because I wouldn't have known what to look for specifically. And there's also the possibility that the other fish that spent 4 weeks with him in the qt before he got sick might also be subclinically infected and have already passed it on into the main tank. So is there even a point in trying to disinfect the hospital and qt tanks now?

[brewmaster15]

Bleach is your best choice for disinfecting a tank.. unscented, regular non detergent bleach.

You could also drain it and let it all dry..then spray all surfaces with 90 % rubbing alcohol and let air dry.

[Willie]

I would make up a 20% Clorox solution and pour enough into the tank to cover the bottom surface for 20 minutes. You then lay the tank on one side for 20 minutes to sterilize it, lay it on another side for 20 minutes, then another side... Then just let it air dry (rinsing is unnecessary). Soaking any other item that may have been contaminated in 20% Clorox for 20 minutes will also disinfect them. The active ingredient in Clorox, sodium hypochlorite, will deactivate fungi, bacteria and viruses. It will 100% dissipate when dry and will not stain your items like potassium permanganate. We do have testosterone-types that want to "nuke" that tank, but that's not necessary. All that will achieve is to chemically damage the hardware though oxidation.

It's great that you have a quarantine tank and are cognizant of controlling disease. In general, disease organisms (pathogens) can only reproduce inside their target host. Even then, there needs to be a critical mass to achieve infection. One worm, one fungal mycelium, one bacterium, one virus particle ... will not cause disease. Neither will 10, 100 or 1,000. So just dumping out all the water, cleaning the surfaces, rinsing and associated hygiene steps will drop the pathogen population to the point of irrelevance. I have a quarantine/sick tank that gets used 4 - 5 times a year. After I successfully/unsuccessfully treat a sick fish, the tank gets wiped down and runs empty until the next time it's needed. Disease pathogens, if they remain, starve out without fish around.

[brewmaster15]

I would make up a 20% Clorox solution and pour enough into the tank to cover the bottom surface for 20 minutes. You then lay the tank on one side for 20 minutes to sterilize it, lay it on another side for 20 minutes, then another side... Then just let it air dry (rinsing is unnecessary). Soaking any other item that may have been contaminated in 20% Clorox for 20 minutes will also disinfect them. The active ingredient in Clorox, sodium hypochlorite, will deactivate fungi, bacteria and viruses. It will 100% dissipate when dry and will not stain your items like potassium permanganate. We do have testosterone-types that want to "nuke" that tank, but that's not necessary. All that will achieve is to chemically damage the hardware though oxidation.

It's great that you have a quarantine tank and are cognizant of controlling disease. In general, disease organisms (pathogens) can only reproduce inside their target host. Even then, there needs to be a critical mass to achieve infection. One worm, one fungal mycelium, one bacterium, one virus particle ... will not cause disease. Neither will 10, 100 or 1,000. So just dumping out all the water, cleaning the surfaces, rinsing and associated hygiene steps will drop the pathogen population to the point of irrelevance. I have a quarantine/sick tank that gets used 4 - 5 times a year. After I successfully/unsuccessfully treat a sick fish, the tank gets wiped down and runs empty until the next time it's needed. Disease pathogens, if they remain, starve out without fish around.

Willie,
Generally I agree with you on how most pathogens will die out without the host fish, but there are exceptions..for example... Mycobacterium marinum, Fish tuberculosis is one that is showing a persistence, includng having been found to possibly make spore -like particles.(endospores)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906719/

Bacteria have the ability to adapt to different growth conditions and to survive in various environments. They have also the capacity to enter into dormant states and some bacteria form spores when exposed to stresses such as starvation and oxygen deprivation. Sporulation has been demonstrated in a number of different bacteria but Mycobacterium spp. have been considered to be non-sporulating bacteria. We recently provided evidence that Mycobacterium marinum and likely also Mycobacterium bovis bacillus Calmette–Guérin can form spores. Mycobacterial spores were detected in old cultures and our findings suggest that sporulation might be an adaptation of lifestyle for mycobacteria under stress. Here we will discuss our current understanding of growth, cell division, and sporulation in mycobacteria.

Even without spore formation, Mycobacterium marinum can survive for weeks to months on surfaces.This is an article on it that is an SOP for a fish research university...
https://www.colorado.edu/ehs/sites/d...m-marinium.pdf

Mycobacteria can survive for weeks to months on surfaces in the absence of sunlight.
Personnel should wash their hands frequently while working in and before leaving the
laboratory. Personal items including waters bottles, cell phones, car keys, etc., should be stored
in such a way as to avoid contamination and should be accessed only when the laboratory
exercise is completed, lab coats and gloves are removed, and hands are washed

its a pretty serious pathogen thats human transmissible,




I would prefer to not take a chance, I would not necessarily consider myself the "testosterone type" that want to "nuke a Tank" but I am not foolish enough to take a chance when I don't need to. Discus are expensive. I think its always a good idea to start with a clean tank...just in case.

[Johanna]

Thank you for the answers! I've been googling for an hour or two and it seems to be next to impossible to find "pure" chemicals here. I can't find bleach as such. Sodium hypochlorite is often one component but there are always other chemicals mixed with it. Most are scented when you read the label carefully. I don't know if they would be safe to use, probably not...

Virkon S is used a lot in veterinary medicine etc, wonder if it could be useful for this purpose as well?

[brewmaster15]

How about pool and spa chemicals... dry chlorine from a pool supply will work..

Is alcohol availible? Its usually at every pharmacy out there...

Virkon s would work but I would not trust it to not leave residuals in the aquarium

[Johanna]

Oh, I forgot the alcohol. That could be my best option. I'll ask the pharmacy tomorrow. Pool stuff is probably hard to find, we don't really have a great climate for them in Finland

[Willie]

Al;

Mycobacterium marinum behaves like every other members of its genus, such as M. leprae, M. tuberculosis, etc. It's omni-present and only poses a risk when it enters via a deep gash. Fish to fish transmission has not been documented. To kill bacteria in spore form would require hot chlorinated water, the kind of procedure required to clean hot tubs. Standard soaking in chlorine would not do it. Bacteria are omni-present so the tank would be contaminated shortly after the cleaning process unless it was kept in a clean room.

The point I'm trying to make is that a single cell/spore does not cause disease. If you put 1, 10, 100 or 1,000 bacteria into a bacterial broth and grew it, nothing will happen. A significant inoculum is needed to start the culture.

[brewmaster15]

Al;

Mycobacterium marinum behaves like every other members of its genus, such as M. leprae, M. tuberculosis, etc. It's omni-present and only poses a risk when it enters via a deep gash. Fish to fish transmission has not been documented. To kill bacteria in spore form would require hot chlorinated water, the kind of procedure required to clean hot tubs. Standard soaking in chlorine would not do it. Bacteria are omni-present so the tank would be contaminated shortly after the cleaning process unless it was kept in a clean room.

The point I'm trying to make is that a single cell/spore does not cause disease. If you put 1, 10, 100 or 1,000 bacteria into a bacterial broth and grew it, nothing will happen. A significant inoculum is needed to start the culture.

Willie the point I am trying to make is why take chances when 99.9 % of the time a hobbyist does not know what killed their fish. I would rather err on the side of caution .

The point you make on the numbers needed for infection is valid... but again how would you know what levels your tank had.. you wouldnt. Nuking a hospital tank may be excessive but its prudent as well.


We change a ton of water just incase we aren't changing enough. .. extend that same line of thought to disease prevention and it makes sense to do the most you can..not the least.

Thats just me though... everyone should make their own call on that... not saying you are wrong... but my perspective on this doesnt align with yours this time.

[Discus Fever]

You can use vinegar and water as well

[Johanna]

You can use vinegar and water as well

Can I have more info on this, please?