Help My Mollys All Died :(

Gleo

New Member
Messages
8
Reaction score
10
Points
3
I’ve had two Mollys for a long time and they recently had 4 babies that grew pretty big... yesterday I removed them, put them in a bowl with water from the original fish tank, drained and cleaned the fish tank, filled it with tap water (which I always do) and put the fish back in the tank once the temperatures matched exactly. Today all 6 Mollys are dead! D: what could’ve killed them? The tank was getting really nasty before I cleaned it... I thought getting all the junk out would be healthier though... what went wrong?
 

Benfreshwater

Valued Member
Messages
217
Reaction score
157
Points
58
Experience
Just started
Did you put any declorinator into the tank and or any water from the old tank? Or just re filled it to the brim with tap water from empty?
 
  • Thread starter
  • Thread Starter
  • #4

Gleo

New Member
Messages
8
Reaction score
10
Points
3
Did you put any declorinator into the tank and or any water from the old tank? Or just re filled it to the brim with tap water from empty?
Filled it completely with new tap water... but the water that was in there came from the same faucet, and when I periodically change a few gallons it’s always with the same tap water

Did you condition the water?
I never have before... they’ve all been happy and healthy in plain tap water from the day I brought them home.
 

Benfreshwater

Valued Member
Messages
217
Reaction score
157
Points
58
Experience
Just started
What size tank? I am surprised you've had no other issues in the past if you have never conditioned the water before.... The shock will of killed them I'd assume. The chlorine in the water is deadly to fish in large exposures
 

Crazycoryfishlady

Well Known Member
Messages
2,075
Reaction score
1,222
Points
148
Experience
5 to 10 years
To be fair I don't use water conditioner anymore either. It doesn't harm my fish, and saves me a bit of money as well with my 16 fish tanks.
I wouldn't say it's always the tap waters fault, but if the tank was really mucky, you may have ended up with an ammonia spike.
I would get a test kit and test your water for ammonia, I think you'll find that is your culprit.

Did you clean the filter too? Or just the tank water?
Not everyones water is treated with chlorine, and not everyones water has harmful amounts.
 
  • Thread starter
  • Thread Starter
  • #7

Gleo

New Member
Messages
8
Reaction score
10
Points
3
What size tank? I am surprised you've had no other issues in the past if you have never conditioned the water before.... The shock will of killed them I'd assume. The chlorine in the water is deadly to fish in large exposures
30 gallon tank. Do you think there’d be more chlorine now than the first time I filled the tank? I’ve never conditioned the water and never had anything like this happen before. I have gobys in the tank too who look fine, only the Mollys died :/
 

Benfreshwater

Valued Member
Messages
217
Reaction score
157
Points
58
Experience
Just started
Like @Crazycoryfishlady said did you clean the filter too? Because you could of removed all good bacteria out of your tank as I'd you was starting a new cycle in the tank as such... Sorry to hear your fish have died though :-(
 

Crazycoryfishlady

Well Known Member
Messages
2,075
Reaction score
1,222
Points
148
Experience
5 to 10 years
30 gallon tank. Do you think there’d be more chlorine now than the first time I filled the tank? I’ve never conditioned the water and never had anything like this happen before. I have gobys in the tank too who look fine, only the Mollys died :/
My gobies were always pretty sensitive, so I don't think it's just the water change that killed them... This does sound like a mystery though.. It's often quite odd for only one species of fish to die overnight.
Are there any other fish?
Exactly how much water did you change? All of it or just a few gallons?
 
  • Thread starter
  • Thread Starter
  • #10

Gleo

New Member
Messages
8
Reaction score
10
Points
3
To be fair I don't use water conditioner anymore either. It doesn't harm my fish, and saves me a bit of money as well with my 16 fish tanks.
I wouldn't say it's always the tap waters fault, but if the tank was really mucky, you may have ended up with an ammonia spike.
I would get a test kit and test your water for ammonia, I think you'll find that is your culprit.

Did you clean the filter too? Or just the tank water?
Not everyones water is treated with chlorine, and not everyones water has harmful amounts.

I cleaned the filter too. The Mollys are allot messier than my other fish so adding 4 more juveniles did make it pretty mucky... would rapidly decreasing the amount of ammonia harm the fish as well?
 

Benfreshwater

Valued Member
Messages
217
Reaction score
157
Points
58
Experience
Just started
Removing all the "good bacteria" from the water and filter will harm the fish. But like said before it's a mystery how only 1 species has died.... Unless the Molly's just weren't as resilient as your other fish...
 
  • Thread starter
  • Thread Starter
  • #12

Gleo

New Member
Messages
8
Reaction score
10
Points
3
My gobies were always pretty sensitive, so I don't think it's just the water change that killed them... This does sound like a mystery though.. It's often quite odd for only one species of fish to die overnight.
Are there any other fish?
Exactly how much water did you change? All of it or just a few gallons?

I changed all the water... I have 4 bumblebee gobys and two little ghost shrimp

Removing all the "good bacteria" from the water and filter will harm the fish. But like said before it's a mystery how only 1 species has died.... Unless the Molly's just weren't as resilient as your other fish...
Thanks, I never thought I’d be removing good bacteria... I’m pretty new to fish tanks, which is why I got Mollys actually because I thought they were especially hardy
 

Benfreshwater

Valued Member
Messages
217
Reaction score
157
Points
58
Experience
Just started
I'm not to clued up on Molly's tbh I have never kept them but it just sounds like you've re started the new tank cycle process..
 

Crazycoryfishlady

Well Known Member
Messages
2,075
Reaction score
1,222
Points
148
Experience
5 to 10 years
I'd definitely invest in a test kit, either the api master freshwater liquid kit or if you can't find that or afford it right now, get a small bottle of test strips including the ammonia one.
It's important to know about ammonia levels in the tank for yourself, and not just what a store might tell you.
You may also want a bottle of beneficial bacteria, if you removed your cycle, this will help it start again.
I use stability for my bottled bacteria.
You can definitely do more harm than good by deep cleaning tanks sometimes.
Cleaning the substrate is never a bad thing, but cleaning too much at once is.
Fish don't like sterile environments, after all, rivers generally aren't perfect water right?
Mollies can be quite tough fish, which is why it's odd to me they died, but now your goal would be to make sure your gobies stay healthy.
You may have to do a water change again in the near future, but I would test with a kit first.
 

CheshireKat

Well Known Member
Messages
1,145
Reaction score
502
Points
133
Experience
More than 10 years
Most of what I'd say has already been addressed. I guess my main thing is why you took them out to clean in the first place. If you're taking fish out to clean or do maintenance, you're probably cleaning too much. Unless you took them out so they don't get sucked up or something?

You said you removed the Molly babies. Did you only remove them? Maybe the stress of being moved killed them? I'd be surprised though because I've moved baby mollies--newborns, even, like just born within a couple hours--into a bucket, left them for a couple hours, and returned and moved them to the tub I'd bought. I recently moved platy fry around too. They're hardy creatures.

But still, genes are different. Or maybe they had something going on already and this was just the catalyst?

To sum up all that's been said and add on:
  • Don't do a deep cleaning of everything all at once to prevent beneficial bacteria from being removed.
  • 100% water changes are never necessary unless you've got a [deadly] outbreak of something that needs to be eradicated only through a complete cleaning. Hopefully that won't ever be the case!
  • Replacing filter cartridges/media will remove beneficial bacteria. Just swish it around in removed tank water during a water change when the media is really dirty and replace the cartridge when it's falling apart. I recommend keeping the old cartridge, or a piece of it, in the tank while the new media is accumulating BB and such.
  • Start doing about 50% water changes and vacuuming weekly. Mollies can be pretty messy and you have gobies and shrimp, they need clean water. If it seems like that's not enough (maybe there's a lot of never-ending muck you're siphoning out), try biweekly.
  • I recommend testing your water for chlorine and chloramine if you don't have a well. Or try looking up your city/county's water reports to see what's in your water, that way you have a better idea of potential issues. (it's also rather enlightening for you as well, especially if you drink it) You may not need water conditioner, although personally it's better safe than sorry. It at least gives me a peace of mind. I use Seachem Prime, which is highly recommended by many. It also detoxifies ammonia so if you have ammonia (you shouldn't if your tank is cycled and if there's none in your tap water), it won't harm your fish.
  • Get a test kit such as the API Master Freshwater kit. This allows you to monitor your tank on your own and can tell you what's going on in the water that's not visible.
 

Faytaya

Valued Member
Messages
400
Reaction score
165
Points
38
Experience
Just started
Nobody mentioned one thing that might have also happened; shock from water content changes. If your fish acclimated to dirty water, removing all the water for a change at the same time would cause a sudden fluctuation in water quality which may have caused them to go into shock. If they've been living in dirty water for a while before the change, I'd wager your change killed them or at least added to the problem. So to sum up, there's a collection of things you may have done wrong that cumulatively did this. I'm so sorry you lost your fish. Next time if they've lived in dirty water for a while, gradually change out water to avoid shocking your fish. Best of luck.
 

CheshireKat

Well Known Member
Messages
1,145
Reaction score
502
Points
133
Experience
More than 10 years
Nobody mentioned one thing that might have also happened; shock from water content changes. If your fish acclimated to dirty water, removing all the water for a change at the same time would cause a sudden fluctuation in water quality which may have caused them to go into shock. If they've been living in dirty water for a while before the change, I'd wager your change killed them or at least added to the problem. So to sum up, there's a collection of things you may have done wrong that cumulatively did this. I'm so sorry you lost your fish. Next time if they've lived in dirty water for a while, gradually change out water to avoid shocking your fish. Best of luck.
Well, I did say that maybe the stress of moving them killed them. I didn't go into detail, but this is what I was thinking. I'm on my tablet and haven't eaten breakfast or lunch, so I don't think my brain and fingers are quite on the same page; one's thinking a bunch of different things, the other is struggling to keep up and type everything :emoji_sweat_smile:
 

Faytaya

Valued Member
Messages
400
Reaction score
165
Points
38
Experience
Just started
Well, I did say that maybe the stress of moving them killed them. I didn't go into detail, but this is what I was thinking. I'm on my tablet and haven't eaten breakfast or lunch, so I don't think my brain and fingers are quite on the same page; one's thinking a bunch of different things, the other is struggling to keep up and type everything :emoji_sweat_smile:
Don't worry, I have my moments too XD
 

jdhef

Moderator
Messages
14,214
Reaction score
3,220
Points
583
Experience
More than 10 years
I just wanted to mention that one of the reasons water companies put chlorine in the water is to kill bacteria...and of course it is bacteria in your filter that cycles your tank.
 

Momgoose56

Fishlore VIP
Messages
5,334
Reaction score
3,209
Points
433
Experience
More than 10 years
All municipal water companies in the US treat public water with some type of microbicide- usually chlorine or chloramine. If you use city water, completely "drained" aand refilled your tank and didn't use a dechlorinator, the clorine in the water probably contributed to the death of your fish. You could have a drastically different pH between your tank water and what comes out of your tap. If you don't do regular weekly partial water changes and suddenly change ALL the tank water, you could have significantly altered the pH in the tank which will also kill fish. This concept also applies to sudden changes in nitrate levels in your tank. I suggest getting a good test kit (API Master test kit is good) that measures pH, ammonia, nitrite and nitrates, start testing your water, do weekly partial (30-50%) water changes and vacuum substrate to keep nitrates well under 40 ppm.
 
Toggle Sidebar

Aquarium Calculator

Follow FishLore!





Top Bottom