Pandemic in the tank! Help!

[reacole]

Hello, I have a Biorb 30L tropical tank, well established (had it for 8-9 years now). In April 2022 I bought 7 guppies to replace the tetras I had for years who had slowly died. Since then, I am now down to 4 fish and one is clearly not well - I'm guessing it will probably be dead by tomorrow. Its body is all crooked and struggling to swim.
I tested the water last week when I found another dead fish and all tests (PH, nitrate, nitrite, ammonia) were clear. What could it be? I initially thought the shop had sold me some dodgy/old fish (not a shop I had used before), but now I'm concerned it is some sort of infectious disease? What can I do to treat the tank and try and save the remaining (soon to be) 3 fish? Thanks a lot!

 

[itiwhetu]

What are your parameters? Guppies and Tetras need different conditions

 

[Colin_T]

Pictures and video of the fish?

Have you added anything to the tank in the 2 weeks before they started to die?

How soon after you got them did the first one die?
What symptoms do they have?

How often do you do water changes and how much do you change?
Do you gravel clean the substrate when you do a water change?

What sort of filter is on the tank?
How often and how do you clean the filter?

What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

--------------------
WHAT TO DO NOW.
Wipe the inside of the glass down with a clean sponge.

Do a 75% water change and gravel clean the substrate.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks.

Add some salt.

--------------------
SALT
You can add rock salt (often sold as aquarium salt) or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 2 heaped tablespoons per 20 litres and if there is no improvement after 48 hours, then increase it so there is a total of 4 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate (4 heaped tablespoons per 20 litres) will affect some plants and some snails. The lower dose rate (1-2 heaped tablespoons per 20 litres) will not affect fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

When you first add salt, add the salt to a small bucket of tank water and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.

 

[reacole]

What are your parameters? Guppies and Tetras need different conditions

Hi - I didn't note them down, but ammonia, nitrite and nitrate were all in the clear range as advised by fish shop when I bought the tank years ago. Ph would be in the 7 region, same as fish shop as it is in my area. Sorry I can't be more specific, but I have had guppies before the tetras and those too lived for 2-3 years so I don't think it is anything to do with the water per se.

 

[Essjay]

In London you probably have hard to very hard water, though there are parts which don't have hard water. Look on your water company's website for hardness - you need a number and the unit of measurement as there are several they could use. If in doubt, post a screenshot.

If you do have hard water, that's good for guppies so it shouldn't be the water affecting them.

 

[GaryE]

It isn't the water. They are all crooked, which says a bacterial disease encysted internally.

When you say 'pandemic', as a worldwide epidemic, you're probably correct. There is a pandemic of Mycobacteriosis in the aquarium trade, and what you are seeing fits the disease profile. The symptoms, the timing, the results, and guppies, who are very affected...There is no treatment and no cure, and you just got "a bad batch".

The problem with bacterial disease is we lack the tools to see which bacteria. Getting tests is expensive. If the fish have twisted bodies, rectangular plaques on their flanks, are listeless and unable to eat, have weird swellings, etc, it could be the disease with a thousand symptoms.

The shops don't know because the disease can develop over a period of many months.

 

[reacole]

In London you probably have hard to very hard water, though there are parts which don't have hard water. Look on your water company's website for hardness - you need a number and the unit of measurement as there are several they could use. If in doubt, post a screenshot.

If you do have hard water, that's good for guppies so it shouldn't be the water affecting them.

yes, I do have hard water. The calcium carbonate is 272 ppm and it is classed as hard water indeed.

 

[reacole]

It isn't the water. They are all crooked, which says a bacterial disease encysted internally.

When you say 'pandemic', as a worldwide epidemic, you're probably correct. There is a pandemic of Mycobacteriosis in the aquarium trade, and what you are seeing fits the disease profile. The symptoms, the timing, the results, and guppies, who are very affected...There is no treatment and no cure, and you just got "a bad batch".

The problem with bacterial disease is we lack the tools to see which bacteria. Getting tests is expensive. If the fish have twisted bodies, rectangular plaques on their flanks, are listeless and unable to eat, have weird swellings, etc, it could be the disease with a thousand symptoms.

The shops don't know because the disease can develop over a period of many months.

Thanks Gary. This sounds scary. To be honest I had not noticed any changes in the bodies of the other fish before they died, aside from the fact that they were not swimming much and were 'resting' on the gravel before they died. The one I mentioned before is still swimming around a little but the body is definitely crooked and it is moving around slowly. I guess if there is nothing I can do and can only hope for the best, do I need to do anything aside from water change as and when I want to buy more fish to replace them, on the assumption they might all die soon . What do you think about the suggestion of treating tank with salt given above? I had not heard of this before and concerned as I think guppies are freshwater fish. Thanks.

 

[Essjay]

Salt can be used as a medication in freshwater tanks as the salt is not in the water for longer than 4 weeks maximum, then it's diluted with water changes till it's gone. But if it is Mycobacteriosis it won't help, salt is usually for treating external infections rather than internal.

 

[reacole]

Pictures and video of the fish?

Have you added anything to the tank in the 2 weeks before they started to die?

How soon after you got them did the first one die?
What symptoms do they have?

How often do you do water changes and how much do you change?
Do you gravel clean the substrate when you do a water change?

What sort of filter is on the tank?
How often and how do you clean the filter?

What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

--------------------
WHAT TO DO NOW.
Wipe the inside of the glass down with a clean sponge.

Do a 75% water change and gravel clean the substrate.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks.

Add some salt.

--------------------
SALT
You can add rock salt (often sold as aquarium salt) or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 2 heaped tablespoons per 20 litres and if there is no improvement after 48 hours, then increase it so there is a total of 4 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate (4 heaped tablespoons per 20 litres) will affect some plants and some snails. The lower dose rate (1-2 heaped tablespoons per 20 litres) will not affect fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

When you first add salt, add the salt to a small bucket of tank water and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.

Hello Colin, thanks for your reply. Sorry - I cannot post a video or photo at the moment as don't have a suitable device connected to this computer but will try later.

In answer to your questions:

Have you added anything to the tank in the 2 weeks before they started to die? No - the last tetra died a few days before (after 5 years or so), I did a 75% water change and added the guppies. First one died after a couple of months after.

How soon after you got them did the first one die? ca. 2 months
What symptoms do they have? I'm not sure. I just found that one dead.

How often do you do water changes and how much do you change? Every other week I change 75% water and clean all rocks and 'accessories' - I have followed this pattern for years.
Do you gravel clean the substrate when you do a water change? Not sure what you mean exactly but I do use a pump to clean the gravel (Biorb has small rocks) although I don't take it out of the tank

What sort of filter is on the tank? This sort https://www.amazon.co.uk/dp/B005DSAMNY/?tag=
How often and how do you clean the filter? Once a year and no, I don't clean it.

 

[Essjay]

With Biorbs, the main biological filter medium is the rocks. The small container in the service pack contains something to catch the bits in the water (a sponge or foam, I think) and carbon or a carbon/zeolite mixture (plain black for just carbon; black and white for the mixture). Changing this should not cause problem as the rocks are the main filter medium. But.....

When you say you clean the rocks, how do you do that? Just siphon out the mess between the rocks, or take the rocks out and scrub them under the tap?

 

[reacole]

With Biorbs, the main biological filter medium is the rocks. The small container in the service pack contains something to catch the bits in the water (a sponge or foam, I think) and carbon or a carbon/zeolite mixture (plain black for just carbon; black and white for the mixture). Changing this should not cause problem as the rocks are the main filter medium. But.....

When you say you clean the rocks, how do you do that? Just siphon out the mess between the rocks, or take the rocks out and scrub them under the tap?

just siphon!

 

[reacole]

I have made a 30 secs video but it won't let me post it - it says it is too big.

 

[GaryE]

If I am right, and I love to be wrong, don't replace the fish til after they are all gone, and do not let them die in the tank. The Myco has to break out of the cyst the fish creates to survive, and when the fish is dead, it needs a new home. So if a full blown Myco case is present, that point where the other fish are nosing around the dead or dying one is the point of transmission.

I assume all farm-raised fish have it, but they do have defenses. The problem comes when they are run down. It is also a salt water problem, and seems very dangerous to fish whose earlier evolution was marine, moving into freshwater. I see it more on hard water livebearers, rainbows, etc. You live with it, and so do they, but when a dead one releaser a wave of homeless killers, the fish defenses are simply overwhelmed. Normally, they encyst the pathogen. But a huge number all at once is too much.

The cysts only cause twisting if they happen to form on the spine. Elsewhere, you don't see them.

Myco are tough beasts. They can survive pure bleach. If a human gets it (i did) they have to have an open cut they stick in the water (I'm a bit of a genius that way), at the same time as a fish has a full blown fatal case. Plus we have to be extra run down or immune compromised. It took 6 months of an antibiotic cocktail to cure. Scary, but very few cases exist - it's rare. I don't win lotteries - I win rare fish transfer problems! But if you have a cat, you are many many more times likely to pick something up from him or her.

 

[reacole]

If I am right, and I love to be wrong, don't replace the fish til after they are all gone, and do not let them die in the tank. The Myco has to break out of the cyst the fish creates to survive, and when the fish is dead, it needs a new home. So if a full blown Myco case is present, that point where the other fish are nosing around the dead or dying one is the point of transmission.

I assume all farm-raised fish have it, but they do have defenses. The problem comes when they are run down. It is also a salt water problem, and seems very dangerous to fish whose earlier evolution was marine, moving into freshwater. I see it more on hard water livebearers, rainbows, etc. You live with it, and so do they, but when a dead one releaser a wave of homeless killers, the fish defenses are simply overwhelmed. Normally, they encyst the pathogen. But a huge number all at once is too much.

The cysts only cause twisting if they happen to form on the spine. Elsewhere, you don't see them.

Myco are tough beasts. They can survive pure bleach. If a human gets it (i did) they have to have an open cut they stick in the water (I'm a bit of a genius that way), at the same time as a fish has a full blown fatal case. Plus we have to be extra run down or immune compromised. It took 6 months of an antibiotic cocktail to cure. Scary, but very few cases exist - it's rare. I don't win lotteries - I win rare fish transfer problems! But if you have a cat, you are many many more times likely to pick something up from him or her.

OMG this scares me right off! I'm 8 months pregnant so I really don't want to be messing about with a potential pathogen I could get from my fish!!! What do I do? Take this one out of the tank and wait until it's dead? Do I just put it in a small container with tank water? I hope you are wrong as this is scary!