Cories dying again

[jaylach]

You state that the water temperature varies between 76-81F. If the temperature changes frequently and quickly it could be stressful. Does this tank have a heater?

 

[Essjay]

It would really be better to keep all this info the same thread, rather than scattered threads across the forum. It gets really confusing when that happens

I have merged the two threads.

 

[jaylach]

I have merged the two threads.

I've had this problem with my computer help forums. Some people think that putting the question all over the place will get them more responses but the opposite seems to be the case.

 

[GaryE]

When the problem develops with the Corys, how long have they been in the tank?

 

[VioletThePurple]

This sounds a lot like internal parasites. Some pictures are really the only way to tell, but I have lost Corydoras to internal parasites before and they demonstrated many of those same symptoms. Luckily for you, General Cure is super easy to find and should knock out any internal issues the fish have. Remember when dosing with medicine, make sure there is no carbon in the filter. Pictures would be greatly appreciated.

I've heard of this but I was told that a sickness wouldn't kill them as quickly as they're dying off. They die a day after showing symptoms. I just lost another one and it was bleeding only after it died. I can't get a pic of any sick cories until the rest get sick and die off because of how fast they die after symptoms.

 

[VioletThePurple]

When the problem develops with the Corys, how long have they been in the tank?

A few months, it's not new.

 

[jaylach]

I recently lost 6 corys and 6 black skirt tetras due to introducing a new live plant that seems to have been contaminated. Have you added anything new to the tank?

 

[VioletThePurple]

I recently lost 6 corys and 6 black skirt tetras due to introducing a new live plant that seems to have been contaminated. Have you added anything new to the tank?

I added an amazon sword. How would I know if it's contaminated?

 

[Deleted member 149562]

I added an amazon sword. How would I know if it's contaminated?

Where did you get the plant from?

There is a possibility, albeit remote, that contamination can be from inadvertant use of a garden strength pesticide....a well meaning member of staff in the store trying to be helpful etc when faced with a new delivery of plants that have snails etc on them and pesticide used.

Not an unheard of incident sadly and it not only kills the pests on the plants but can wipe out the fish in hours too.

 

[VioletThePurple]

You state that the water temperature varies between 76-81F. If the temperature changes frequently and quickly it could be stressful. Does this tank have a heater?

Yes, it does have a heater. The temperature changes day to day but most of the time stays at 78F.

 

[jaylach]

I added an amazon sword. How would I know if it's contaminated?

Ahhh, because your fish died... ? You can't totally know if the new plant killed your fish. If the fish died within a few days after adding the plant and everything was fine before it would indicate that the new plant was at fault but that is hard to actually prove.

 

[VioletThePurple]

Where did you get the plant from?

There is a possibility, albeit remote, that contamination can be from inadvertant use of a garden strength pesticide....a well meaning member of staff in the store trying to be helpful etc when faced with a new delivery of plants that have snails etc on them and pesticide used.

Not an unheard of incident sadly and it not only kills the pests on the plants but can wipe out the fish in hours too.

You said it can wipe them out in hours. The plant is relatively new but not that new, it's been a little over a week since I added it, I don't remember if that was the same time the cories started having problems or before that. If it is the plant, I'm not sure why only the cories are affected and that they're dying off one by one. I would think contamination would kill all at once.

I just buy from the usual PetSmart, all the other plants I bought from them seem fine and never have snails. My LFS is hours away so I can only get from chain pet stores.

 

[VioletThePurple]

Ahhh, because your fish died... ? You can't totally know if the new plant killed your fish. If the fish died within a few days after adding the plant and everything was fine before it would indicate that the new plant was at fault but that is hard to actually prove.

I just mean that there's other reasons my fish could have died. I don't exactly remember when the fish started having problems but it could've been the same time. What else would I do? Should I remove the plant?

 

[jaylach]

I just mean that there's other reasons my fish could have died. I don't exactly remember when the fish started having problems but it could've been the same time. What else would I do? Should I remove the plant?

Yes, remove the plant and do a major water change. Actually removing the plant probably no longer matters but still do. If you have an isolation tank remove the live fish and put in isolation to help if the plant held a toxin. Do a few as close as you can to 100% water changes over a few days to flush the tank of possible toxins. Especially if a toxin was involved you may very well need to re-cycle the tank.

As an important note... If any of the main people here give different advice they are probably giving you better info.

 

[Deleted member 149562]

Cories are one of the most sensitive fish that you can own. They are often one of the first to notice and thus react to any contamination or issue with the water chemistry. Their sensitivity is such that they can die off very quickly if the water chemistry or other contamination is not sourced and handled quickly.

Something like a pesticide used on a plant, they will pick that up very quickly and become unwell and/or die within a very short space of time.

Apart from the plant, what else have you put into the aquarium, have you changed your routine maintenance for any reason recently.....sit and think back through what you might have done differently, what you might have missed doing, check the water source incase the water company flushed the supply pipes as that can sometimes affect the way fish behave and can be detrimental to their health

When fish start to die for no apparent reason, you have to make a mental list of what you have done, what you didn't do, has there been any changes in their food, did you do anything with the substrate differently than normal....mentally tick box everything.....if away for a time, also check for power failures whilst away as that can have a detrimental effect on an aquarium.

Don't get down in the dumps about what has happened as that isn't going to make things better....do a list mentally or write it down of all the potential things that could have triggered this to happen

The mention elsewhere about the Betta attacking fish in the aquarium...again, Cories are very susceptable to stressful conditions, that might have had an effect on them

Do some detective work, eliminate all possibilities...but don't get dispondent or disillusioned cos these things happen to be best fishkeepers and sometimes you can find the issue but often you simply can't.