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Whole batch of molly and guppy juveniles died over night.


ScandiDefense
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Hi everyone. Unfortunately something bad happened again to my tanks and i need some help.

I have been breeding guppies and black mollies for a few months now. I would place the newborn fries in a small tank for a few weeks (until they are about the same size like my adult tetras) and then i would transfer them to a bigger tank and there they will spend a few more weeks with my adult tetras before they get big enough and get shifted to the adult molly tank.

My first batch of black mollies have grown up and i have placed them in the adult tank alongside the adult mollies (their parents). 

The guppies that gave birth to my 1st generation of guppies have all passed on. And all of a sudden my 1st generation of juvenile guppies started dying in large numbers (in the tetra tank). They would grow to a certain size and when they reached that size then they would die. And since most of them are born at around the same time, a lot of them reached that "certain size" at the same time and then they died. I can't seem to find the reason for the cause of death.

My 2nd batch of black mollies juveniles is also experiencing this same strange thing. They reach a certain size and then they would die. The adult tetras that share the tanks with them are doing fine. Happily swimming around as if nothing is wrong.

Btw, i change my waters once a week. All tanks are bare bottom and i am using a simple sponge filter. A friend of mine said it could be due to bad genetics. I desperately wanna know what i am doing wrong here.  I want to stop the unnecessary dying!!! Thank you so much in advance. 

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Hi, so sorry, that really sucks. I'm wondering do you test the water in the grow out tank? Can you tell us what the parameters are. 

My first guess is yes it's probably genetics this can happen with them. @Colu and maybe @Odd Duck could help here. Did you notice any physical signs? Any behavioral? Anything might help give us a clue to assist you better. 

Anecdotally I was wondering myself about some sudden guppy deaths. I recently had some adult guppies die and everyone else in the tank was fine. They came from good stock too. So out of curiousity I tested the water pH was a little low but my usual hard water turned totally soft that may not have helped them. I added Equilibrium and that really seemed to help. I only say that because it effected my guppy population only and I'd tested the water out of curiosity. 

Edited by xXInkedPhoenixX
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Uhm i haven't gotten around to getting a water test kit yet. 

As to my observation about their behaviour, uhm i noticed the guppies were less active and the stayed still at the surface one or two days before the sudden death.... aa for the mollies, they huddled in a big ball at one corner of the tank! And i saw some mollies jumping and sticking on the sides of the tank..... Fyi the guppies died one day earlier than the mollies.....

I haven't bought new fish for at least 6 months. All these fishes have been with me for a minimum of 6 months so stress due to improper acclimating is not in the picture.

I do water changes once a week. But this week was a nightmare for me. On monday i saw my goldfishes in another tank was having some fin rot and white spots so i did a water change and added salt. Tuesday - the juvenile guppies died by the dozen and i did a water change and added salt. Wednesday - the newborn cube tank had a lot of detritus worm and i did a water change. Thursday - black molly juveniles huddled in a corner and more dead guppy juveniles so i did a water change again. This morning - most black molly juveniles died. And i expect to find more dead when i return home later.☹️ I have totally no idea what is causing the deaths. I haven't changed anything to their routine.....

Btw in case it helps, i live in malaysia and this week has been extremely hot due to the haze (neighbouring country doing open burning of the forest and farm). The temperature is 32c - 33c. I wonder could it be due to the hot weather. But malaysian weather is hot year round....

Edited by ScandiDefense
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Sorry to hear that your are having losses.

That kinda sounds like ammonia poisoning to me. You should get yourself a test kit, otherwise people can't really help you.

Pure breed guppies are indeed getting genetically weak, but losing every fish in one day does not sound related to genetics really.

I would do a big water change right now and get a test kit asap

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I have done 2 big water changes this week.... very demoralizing indeed seeing them dropping like flies.... weird thing is the tetras are doing fine.... very weird indeed.

On 4/14/2023 at 1:58 PM, Lennie said:

Sorry to hear that your are having losses.

That kinda sounds like ammonia poisoning to me. You should get yourself a test kit, otherwise people can't really help you.

Pure breed guppies are indeed getting genetically weak, but losing every fish in one day does not sound related to genetics really.

I would do a big water change right now and get a test kit asap

 

Edited by ScandiDefense
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On 4/14/2023 at 9:01 AM, ScandiDefense said:

I have done 2 big water changes this week.... very demoralizing indeed seeing them dropping like flies.... weird thing is the tetras are doing fine.... very weird indeed.

Some fish can tolerate bad conditions better than others. Like a zebra danio being much hardier than a discus for example. So tetras doing okay might not be a good sign of well being.

How are the adults doing? How long has your tank been running/was it cycled? Have you introduced too many babies at once so your cycle could not handle it maybe?

 

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On 4/13/2023 at 10:14 PM, ScandiDefense said:

My first batch of black mollies have grown up and i have placed them in the adult tank alongside the adult mollies (their parents). 

The guppies that gave birth to my 1st generation of guppies have all passed on. And all of a sudden my 1st generation of juvenile guppies started dying in large numbers (in the tetra tank). They would grow to a certain size and when they reached that size then they would die. And since most of them are born at around the same time, a lot of them reached that "certain size" at the same time and then they died. I can't seem to find the reason for the cause of death.

My 2nd batch of black mollies juveniles is also experiencing this same strange thing. They reach a certain size and then they would die. The adult tetras that share the tanks with them are doing fine. Happily swimming around as if nothing is wrong.

Can you let us know your water testing results, food schedule, and what types of foods you feed them?

It could be something like a deficiency causing them to not develop fully.

On 4/13/2023 at 10:14 PM, ScandiDefense said:

Btw, i change my waters once a week. All tanks are bare bottom and i am using a simple sponge filter. A friend of mine said it could be due to bad genetics. I desperately wanna know what i am doing wrong here.  I want to stop the unnecessary dying!!! Thank you so much in advance. 

It could be genetics, but the timing thing is a bit weird.

On 4/13/2023 at 10:32 PM, ScandiDefense said:

as for the mollies, they huddled in a big ball at one corner of the tank! And i saw some mollies jumping and sticking on the sides of the tank..... Fyi the guppies died one day earlier than the mollies.....

This is usually indicative of a water issue.  It could be ammonia, PH, or oxygenation.  Do you normally add aquarium salt for these fish? Are you able to add an extra air stone?

On 4/13/2023 at 10:32 PM, ScandiDefense said:

Btw in case it helps, i live in malaysia and this week has been extremely hot due to the haze (neighbouring country doing open burning of the forest and farm). The temperature is 32c - 33c. I wonder could it be due to the hot weather. But malaysian weather is hot year round....

Ah, this makes a LOT of sense.  When it comes to the forest issues, is there a chance that the water you're using is affected?  Is it from the water table in your area directly via a well or filtered in any way?  Are you seeing deaths as a result of some amount of time due to those types of activities locally or have you experienced deaths at different times?  Something like fertilizers being used is also a common contaminant that causes a wave of deaths in a tank.

Secondly, are you able to store water in any way for your tanks to give it time to age before being used in the aquariums specifically?

Edited by nabokovfan87
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Heat also depletes oxygen, adding an airstone would help. Them huddling at the top tells me they were probably looking for air. It can also be a water parameter issue and I suspect it could be both. Heat can raise bacteria levels and lots of fish waste can speed that process up in grow out tanks. 

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The black molly juveniles were huddled at the very bottom of the tank. I will add an airstone later when i get home. Thank you so much for helping!

Uhm i haven't gotten around to getting a test kit yet.  I feed them twice a day ie once in the morning before i go out and once when i get home. I feed them crushed pellets. Yeah i do add aquarium salt when i do water changes. My water supply is from the tap and i use dechlorinators.

On 4/14/2023 at 2:13 PM, nabokovfan87 said:

Can you let us know your water testing results, food schedule, and what types of foods you feed them?

It could be something like a deficiency causing them to not develop fully.

It could be genetics, but the timing thing is a bit weird.

This is usually indicative of a water issue.  It could be ammonia, PH, or oxygenation.  Do you normally add aquarium salt for these fish? Are you able to add an extra air stone?

Ah, this makes a LOT of sense.  When it comes to the forest issues, is there a chance that the water you're using is affected?  Is it from the water table in your area directly via a well or filtered in any way?  Are you seeing deaths as a result of some amount of time due to those types of activities locally or have you experienced deaths at different times?  Something like fertilizers being used is also a common contaminant that causes a wave of deaths in a tank.

Secondly, are you able to store water in any way for your tanks to give it time to age before being used in the aquariums specifically?

 

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Oh i see... maybe the tetras are hardier than those juveniles. The adult mollies are doing fine. They are in a separate tank. Uhm my tanks are have been running for 8 months plus i think. All my tanks are 15 gallons. And i am not sure how much fish should be in a 15 gallon tank...

On 4/14/2023 at 2:11 PM, Lennie said:

Some fish can tolerate bad conditions better than others. Like a zebra danio being much hardier than a discus for example. So tetras doing okay might not be a good sign of well being.

How are the adults doing? How long has your tank been running/was it cycled? Have you introduced too many babies at once so your cycle could not handle it maybe?

 

 

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On 4/13/2023 at 11:25 PM, ScandiDefense said:

crushed pellets.

What kind?

On 4/13/2023 at 11:33 PM, ScandiDefense said:

And i am not sure how much fish should be in a 15 gallon tank...

AqAdvisor recommends about 8-10 just based on water volume.  I'm sure a lot of people have more, just requires more maintenance.

Note, this would be meaning, full grown adults, not breeding (sorted).

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Uhm what kind as in? Well it is some sort of fast growth pellets that i have been feeding them for the past 8 months. 8-10 adults on 15 gallon. Anything more would be overstocked? For breeder tanks, any recommendations? As in how much would  be overstocked?

On 4/14/2023 at 2:58 PM, nabokovfan87 said:

What kind?

AqAdvisor recommends about 8-10 just based on water volume.  I'm sure a lot of people have more, just requires more maintenance.

Note, this would be meaning, full grown adults, not breeding (sorted).

 

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I agree sounds like something wrong with your water parameters such as high levels of ammonia nitrite or nitrate or you pH and KH could be to low that why you had a mass die off of your guppies and Molly with out noing your water parameters ammonia nitrite nitrate pH kH it difficult to diagnose if it were ammonia or nitrate or nitrite poisoning the most effective treatment is aquarium salt 1 table spoon for 1 gallon it help to speed up the  removal ammonia from fish blood and it acts as a natural barrier thought  chloride ions to prevent the uptake of nitrite and nitrate @ScandiDefense

Edited by Colu
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On 4/14/2023 at 12:08 AM, ScandiDefense said:

hm what kind as in? Well it is some sort of fast growth pellets that i have been feeding them for the past 8 months. 8-10 adults on 15 gallon. Anything more would be overstocked? For breeder tanks, any recommendations? As in how much would  be overstocked?

Not really sure.  The best thing I can do is point you towards some of the tours of breeders on the ACO channel.  Usually the higher stock level is handled with more water changes.  If your issue is the source of the water and contamination, increasing water changes wouldn't help.  That's why I was asking about your ability to store water, if you're on a well, etc.

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As others have said, mass die offs are pretty much always a water parameter issue or toxin of some sort in the water.  I’m afraid until you can tell us what your water parameters are it’s unlikely we’ll be able to make smart recommendations when we don’t have enough information.  If we don’t know that your tap water is safe, water changes may not help.  Instead they could make it worse.  As a very rough rule, you can usually get away with around an inch of fish per gallon with sufficiently clean water and enough filtration and aeration.  If you are feeding heavy to grow babies, you need more water per fish.  If you are keeping heavy bodied fish, you need more water per fish.  If you have tiny fish, their mass is decreased and you can have more per gallon.

Most breeders do more frequent water changes so toxins don’t build up in the water with heavy populations and feeding.  Big jumps in the number of fish in the tank could mean your biofiltration is overloaded.  For sure more airstones whenever fish are hanging out at the surface.  But we need to know what your tap water and tank water parameters are to make more than a guess at what’s going wrong.

Edited by Odd Duck
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Thank you so much guys for the effort and all the precious info shared. Latest update:- The last remaining juvenile mollies have died out.... ☹️ I decided to separate my mollies because i dont wanna breed them until i get to the bottom of this mass die out... So this morning, i did a 90% water change and shifted my 4 male adult mollies into the tank (with my 6 tetras). It has been near 10 hours now and the male adult mollies are doing fine in the "cursed" tank. Once again i would like to thank all of you guys for your precious time and info. I really appreciate it from the bottom of my heart. 😌

On 4/14/2023 at 6:17 PM, Colu said:

I agree sounds like something wrong with your water parameters such as high levels of ammonia nitrite or nitrate or you pH and KH could be to low that why you had a mass die off of your guppies and Molly with out noing your water parameters ammonia nitrite nitrate pH kH it difficult to diagnose if it were ammonia or nitrate or nitrite poisoning the most effective treatment is aquarium salt 1 table spoon for 1 gallon it help to speed up the  removal ammonia from fish blood and it acts as a natural barrier thought  chloride ions to prevent the uptake of nitrite and nitrate @ScandiDefense

 

On 4/15/2023 at 2:49 AM, nabokovfan87 said:

Not really sure.  The best thing I can do is point you towards some of the tours of breeders on the ACO channel.  Usually the higher stock level is handled with more water changes.  If your issue is the source of the water and contamination, increasing water changes wouldn't help.  That's why I was asking about your ability to store water, if you're on a well, etc.

 

On 4/15/2023 at 3:37 AM, Odd Duck said:

As others have said, mass die offs are pretty much always a water parameter issue or toxin of some sort in the water.  I’m afraid until you can tell us what your water parameters are it’s unlikely we’ll be able to make smart recommendations when we don’t have enough information.  If we don’t know that your tap water is safe, water changes may not help.  Instead they could make it worse.  As a very rough rule, you can usually get away with around an inch of fish per gallon with sufficiently clean water and enough filtration and aeration.  If you are feeding heavy to grow babies, you need more water per fish.  If you are keeping heavy bodied fish, you need more water per fish.  If you have tiny fish, their mass is decreased and you can have more per gallon.

Most breeders do more frequent water changes so toxins don’t build up in the water with heavy populations and feeding.  Big jumps in the number of fish in the tank could mean your biofiltration is overloaded.  For sure more airstones whenever fish are hanging out at the surface.  But we need to know what your tap water and tank water parameters are to make more than a guess at what’s going wrong.

 

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I found my old test kit anf tested it this morning but the old test kit has expired. Feeling very dejected at the moment. I just shifted my male mollies back with my female mollies. I don't dare to risk them dying in the "cursed" tank. Now only my tetras are left in the "cursed"tank. Thanks for the wishes.  Really hope to get to the bottom of the mystery and then bounce back.

On 4/16/2023 at 4:23 AM, nabokovfan87 said:

Very sorry for your losses. Hoping for the best for you in terms of recovering from this.

 

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The old test kit has expired. I dipped the test strips into the water but the coloration did not change. 

On 4/16/2023 at 12:58 PM, nabokovfan87 said:

What did the testing indicate? Anything?

Is there a drinking water testing kit you may be able to use to verify anything in the tap water? Typically for those you'd send it out to a facility for testing and they email or call with results.

 

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