Tank failing-help!

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JSP

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Hi, I'm new to the forum. I have an established 90 gallon planted,freshwater tank. It's been up for about 10 years and I've not had any problems until now.
Two weeks ago I added 3 juvenile Roseline barbs and 6 juvenile spotted cories. Over the next few days the emperor tetras in the tank started to die. No apparent symptoms, just found dead. It's spread to the other fish and now only a few left in the tank. No gasping or rubbing, no lesions. With a few exceptions, the fish look fine until they're found dead. The last 2 adult Roselines, within 12hrs, turned pale, stopped eating, then died. One of Kuhlis floated aimlessly for a hour or two then died.
I also added new cories and dwarf rainbows from the same source to a 20gal tank and they are just fine so far. The heater was having an issue at the same time, but the temp never dipped below 70.


Tank size: 90 gal
pH: 7
ammonia: 0
nitrite: 0
nitrate:0
kH: 4.2
gH: soft water
tank temp: 75

Volume and Frequency of water changes: 30% every week or two

Chemical Additives or Media in your tank: Fluval 4x filter with standard media, charcoal changed monthly. I use a Vecton 200 UV filter (turned off for meds). I know it's not the best idea, but in desperation, I'm trying Maracyn-2. On day 3 of treatment and lost 2 fish today.

Tank inhabitants: Until recently: 3 10yr clown loaches, 5 adult roseline barbs, 12 emperor tetras, a few Kuli loaches, 2 zebra loaches, 1 adult bristlenose, 6 juvenile spotted cories, 1 farlowella catfish.
Java fern, Cryptocornes, Vallisneria, purchased driftwood that's been in the tank for years.
Recent additions to your tank (living or decoration): 3 juvenile Roseline barbs, 6 juvenile spotted cories

Exposure to chemicals: none

One clown loach, 1 Roseline, the bristlenose, the cories, 1 zebra loach and a Kuhli left. Please help.
 
Hi and welcome to the forum :)

It sounds like one of the new fish (probably the barbs) brought in a bacterial infection that is now killing everything.

If you can post a picture of the fish it usually helps in identifying the problem. :)

----------------------
To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.
When you measure the height, measure from the top of the substrate to the top of the water level.

There is a calculator/ converter in the "How To Tips" at the top of this page that will let you convert litres to gallons if you need it.

You need to remove the carbon from the filter otherwise it will absorb the medication and stop it working.

Wipe the inside of the glass down, do a 75% water change and complete gravel clean. And clean the filter before treating. Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Increase surface turbulence/ aeration when using medications because they reduce the dissolved oxygen in the water.

----------------------
Anti-biotics like Maracyn 2 should only be used as a last resort because improper use can cause drug resistance in bacteria that affect people and animals. Anti-biotics are best used in a bare glass or plastic tank/ container. The less gunk in the tank, the more likelihood of the medication working.

I'm not sure of the directions on the product but normally anti-biotics get treated each day for at least 1 week and no more than 2 weeks. If there is no improvement after 2 days of treatment it probably isn't working. If the problem has not been fixed after a week then the medication is probably ineffective on the disease organism and you will need to try something else. The container/ tank should be gravel cleaned, drained and refilled each day before retreating.

Maracyn 2 contains Minocycline and that will kill the filter bacteria too so you should reduce feeding and monitor the ammonia and nitrite levels over the next month. If you get any ammonia or nitrite readings reduce feeding and do a 75% water change on the tank each day until the readings are back to 0.

A broad spectrum fish medication that treats bacterial, fungal and protozoan infections might have worked as well and would have been a better option with less chance of killing off the filter bacteria.

----------------------
After this has settled you would be better off doing a bigger water change each week or each fortnight. Small water changes (30%) only dilute nutrients and micro-organisms/ disease organisms by a small amount, say 30%. This leaves 70% of the harmful things in the tank with the fish where they continue to build up and can eventually cause problems.

A 50-75% water change is more effective at keeping things clean, with a 75% water change being a better option for people doing fortnightly water changes.

----------------------
If you have very soft water with a general hardness (GH) less than 150ppm, you might want to increase it a bit because rainbowfish and barbs usually do better in slightly harder water.
 
Hi and welcome to the forum :)

It sounds like one of the new fish (probably the barbs) brought in a bacterial infection that is now killing everything.

If you can post a picture of the fish it usually helps in identifying the problem. :)

----------------------
To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.
When you measure the height, measure from the top of the substrate to the top of the water level.

There is a calculator/ converter in the "How To Tips" at the top of this page that will let you convert litres to gallons if you need it.

You need to remove the carbon from the filter otherwise it will absorb the medication and stop it working.

Wipe the inside of the glass down, do a 75% water change and complete gravel clean. And clean the filter before treating. Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Increase surface turbulence/ aeration when using medications because they reduce the dissolved oxygen in the water.

----------------------
Anti-biotics like Maracyn 2 should only be used as a last resort because improper use can cause drug resistance in bacteria that affect people and animals. Anti-biotics are best used in a bare glass or plastic tank/ container. The less gunk in the tank, the more likelihood of the medication working.

I'm not sure of the directions on the product but normally anti-biotics get treated each day for at least 1 week and no more than 2 weeks. If there is no improvement after 2 days of treatment it probably isn't working. If the problem has not been fixed after a week then the medication is probably ineffective on the disease organism and you will need to try something else. The container/ tank should be gravel cleaned, drained and refilled each day before retreating.

Maracyn 2 contains Minocycline and that will kill the filter bacteria too so you should reduce feeding and monitor the ammonia and nitrite levels over the next month. If you get any ammonia or nitrite readings reduce feeding and do a 75% water change on the tank each day until the readings are back to 0.

A broad spectrum fish medication that treats bacterial, fungal and protozoan infections might have worked as well and would have been a better option with less chance of killing off the filter bacteria.

----------------------
After this has settled you would be better off doing a bigger water change each week or each fortnight. Small water changes (30%) only dilute nutrients and micro-organisms/ disease organisms by a small amount, say 30%. This leaves 70% of the harmful things in the tank with the fish where they continue to build up and can eventually cause problems.

A 50-75% water change is more effective at keeping things clean, with a 75% water change being a better option for people doing fortnightly water changes.

----------------------
If you have very soft water with a general hardness (GH) less than 150ppm, you might want to increase it a bit because rainbowfish and barbs usually do better in slightly harder water.
 
Thanks for the prompt reply and help.
I confess that the Maracyn-2 was an act of desperation/panic and not as well thought out as it could have been. In newly deceased fish, there did not seem to be any lesions, raised scales, discolored gills, redness, cloudy eyes or lumps. Sorry there are no photos; unfortunately, there may be another opportunity soon.
I had taken some the precautions: removed carbon, cleaned filter before treatment, increased water flow rate through the filter to improve circulation. The fish have been treated for 4 days now and I'm not sure how effective the meds have been; I'll know more after work today. I've only lost one barb (the remaining one is pale and not eating) since starting the meds. Surprisingly, the catfish are still hanging on including a 10yo Upside Down and the Farlowella. Depending on how things look, I'll start 75% water changes on day 5 or 6.
Do you know of a useful wide spectrum antibiotic that won't hurt the scaleless fish?
I guess the next step is moving the survivors and disinfecting the tank. Thanks again.
 
There are also possibilities that are not the result of pathogens being introduced. There is not enough info to say that this is the case but these possibiities include:

Old tank syndrome (plenty of info on Google). In this scenario something harmful (most often nitrate) builds up gradually over the years. As it is not lethal in the short term your fish adapt to the rising levels as they have risen gradually. (This would reduce the lifespan of the fish but they would appear normal and healthy until they die of organ failure - essentially premature old age). New fish added to such a tank can go into shock and die which would cause ammonia or nitrite spikes. This is the reason why Colin recommends bigger water changes.

The second scenario is that if the substrate is undisturbed for a long time anaerobic bacteria can form. These will consume the nitrates in the tank which is a good thing but a by product of the process is sulphur dioxide which can form in pockets in the substrate. If the subtrate is disturbed, say by doing a good clean before adding new fish, this could easily wipe out the tank as it would cause a sudden pH crash and is poisonous. Sulphur dioxide smells like rotten eggs.
 
The suddenness of this die off would lead me to think it was something introduced with the new acquisitions rather than a tank issue that developed though this is a very valid point.

And when this is a fairly rapid die off without external symptoms, it is generally some internal protozoan. The best treatment in such cases is metronidazole added to the food. This antibiotic is safe for most fish, but is much less effective added to the water so get it into their food. Feed only the medicated food for two weeks. It takes a few days to get going like all antibiotics, and given the few fish left you may not save them. But for the future, this is about the most effective if you do not have a microbiologist to do necropsies on dead fish--and I gather even that is not always certain.

You need to prepare the food yourself, I don't think it is available anywhere. I can explain if asked.
 
There are also possibilities that are not the result of pathogens being introduced. There is not enough info to say that this is the case but these possibiities include:

Old tank syndrome (plenty of info on Google). In this scenario something harmful (most often nitrate) builds up gradually over the years. As it is not lethal in the short term your fish adapt to the rising levels as they have risen gradually. (This would reduce the lifespan of the fish but they would appear normal and healthy until they die of organ failure - essentially premature old age). New fish added to such a tank can go into shock and die which would cause ammonia or nitrite spikes. This is the reason why Colin recommends bigger water changes.

The second scenario is that if the substrate is undisturbed for a long time anaerobic bacteria can form. These will consume the nitrates in the tank which is a good thing but a by product of the process is sulphur dioxide which can form in pockets in the substrate. If the subtrate is disturbed, say by doing a good clean before adding new fish, this could easily wipe out the tank as it would cause a sudden pH crash and is poisonous. Sulphur dioxide smells like rotten eggs.
 
The new fish died after several days and had been quite active and hungry. The first to go were 1-3 yo tetras. They died suddenly - one or two per day; the first wave so to speak. I didn't detect any ammonia or nitrite spikes and haven't had increasing nitrate levels. Wondered about the sulfur pockets-the tank doesn't smell bad and only a couple of the fish showed any distress before dying. I did stir up the gravel more than usual to get ready for the new fish when I changed the water. Is it coincidence that they tended to die at night? Live fish at lights out, dead fish next morning.
 
The suddenness of this die off would lead me to think it was something introduced with the new acquisitions rather than a tank issue that developed though this is a very valid point.

And when this is a fairly rapid die off without external symptoms, it is generally some internal protozoan. The best treatment in such cases is metronidazole added to the food. This antibiotic is safe for most fish, but is much less effective added to the water so get it into their food. Feed only the medicated food for two weeks. It takes a few days to get going like all antibiotics, and given the few fish left you may not save them. But for the future, this is about the most effective if you do not have a microbiologist to do necropsies on dead fish--and I gather even that is not always certain.

You need to prepare the food yourself, I don't think it is available anywhere. I can explain if asked.
 
Is it coincidence that they tended to die at night? Live fish at lights out, dead fish next morning.
It is generally coincidence and rarely has anything to do with lighting. Although in brightly lit tanks, having the lights come on while the tank and room are dark, can stress fish and sick fish might die form that.

In the morning open the curtains or turn the room light on at least 30 minutes (or more) before turning the tank light on. This will reduce the stress on the fish and they won't go from a dark tank to a bright tank instantly.

At night turn the room light on and then turn the tank light off. Wait at least 30 minutes (or more) before turning the room light out. This allows the fish to settle down for the night instead of going from a brightly lit tank to complete darkness instantly.

---------------------
Fish die during the day or night but because we have the lights on during the day we can see them, whereas at night the lights are off for a long time and fish still die but we don't see them until the following morning.

---------------------
Do you know of a useful wide spectrum antibiotic that won't hurt the scaleless fish?
I guess the next step is moving the survivors and disinfecting the tank. Thanks again.
Virtually all anti-biotics are safe for scaleless fish as long as they are not overdosed. However, anti-biotics should only be used for a known bacterial infections and if the Maracyin 2 has not worked then it might be best to avoid using more or different anti-biotics until a more accurate diagnosis is made.

After a week of treating I would simply do a 75% water change and gravel clean the substrate each day for a couple of weeks. This will dilute any disease organisms and the remaining fish might recover without any need for chemicals or anti-biotics.

I wouldn't remove the fish and strip the tank just yet because the stress of chasing them and handling them could damage their skin and allow an infection to get into an otherwise healthy fish.

When you get home, try to get some pictures of the sick or even healthy fish and we will try to see if there is anything on them we can identify.
 
Thanks. Looks like there's an introduced infection of some sort exacerbated by inadequate water changes. The lack of external symptoms, no behavior changes and clean water test results confounded me and I didn't think about protozoa. Ken's fish offers treated flakes if those work. Or I can prepare it myself. I would appreciate some instructions on the best way to prepare and dosage. The fish are accustomed to several forms of food - flake, pellet, freeze dried and frozen (usually blood worms). Can I use the UV filter if the meds are in the food?

Thanks to everyone who has helped me with this. Day 4 Maracyn and no further deaths. I'll pursue
It is generally coincidence and rarely has anything to do with lighting. Although in brightly lit tanks, having the lights come on while the tank and room are dark, can stress fish and sick fish might die form that.

In the morning open the curtains or turn the room light on at least 30 minutes (or more) before turning the tank light on. This will reduce the stress on the fish and they won't go from a dark tank to a bright tank instantly.

At night turn the room light on and then turn the tank light off. Wait at least 30 minutes (or more) before turning the room light out. This allows the fish to settle down for the night instead of going from a brightly lit tank to complete darkness instantly.

---------------------
Fish die during the day or night but because we have the lights on during the day we can see them, whereas at night the lights are off for a long time and fish still die but we don't see them until the following morning.

---------------------

Virtually all anti-biotics are safe for scaleless fish as long as they are not overdosed. However, anti-biotics should only be used for a known bacterial infections and if the Maracyin 2 has not worked then it might be best to avoid using more or different anti-biotics until a more accurate diagnosis is made.

After a week of treating I would simply do a 75% water change and gravel clean the substrate each day for a couple of weeks. This will dilute any disease organisms and the remaining fish might recover without any need for chemicals or anti-biotics.

I wouldn't remove the fish and strip the tank just yet because the stress of chasing them and handling them could damage their skin and allow an infection to get into an otherwise healthy fish.

When you get home, try to get some pictures of the sick or even healthy fish and we will try to see if there is anything on them we can identify.
 
roseline barb-post maracyn2.jpg
farlowella-post Maracyn2.jpg
I try not to light shock them. Turning off the tank light with the room light on brings out the clown loach. The farlowella is the only photographically cooperative catfish.
Day 5 Maracyn2. No further deaths. The remaining Roseline has regained a lot of color but does not appear to be eating. 75% water change and gravel clean tomorrow. Thanks
 
If there has been no deaths for 5 days then it sounds like you might have got it sorted. :)

The roseline barb has a small white spot on the side of its body just above the black line. Keep an eye on that and if it disappears for a few days and then more white spots appear the fish have whitespot or ich. If it stays and gets bigger then post another picture of it because it could be Lymphocystis or the start of an ulcer.
Lymphocystis is a stress virus that will heal up by itself over time but ulcers are a separate issue.

Give the fish a couple of days to start eating. They won't starve and if they had a bacterial infection then their bodies will need time to heal and work properly.
 
If there has been no deaths for 5 days then it sounds like you might have got it sorted. :)

The roseline barb has a small white spot on the side of its body just above the black line. Keep an eye on that and if it disappears for a few days and then more white spots appear the fish have whitespot or ich. If it stays and gets bigger then post another picture of it because it could be Lymphocystis or the start of an ulcer.
Lymphocystis is a stress virus that will heal up by itself over time but ulcers are a separate issue.

Give the fish a couple of days to start eating. They won't starve and if they had a bacterial infection then their bodies will need time to heal and work properly.
 
It is starting to look like the worst is over. Hopefully the white spot will resolve.
What is the recommended post infection procedure? I don't want to stress the survivors and they are going to be stressed from the infection as well as the loss of their tank buddies. So- after a recovery period do I need to strip the tank or is there a gentler way? Thanks for your help.
 

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