Cory’s randomly dying

[efirerobin]

My Cory’s are randomly dying this week, no signs of illness or anything, my water perimeters are all where they should be the temperature is set at 77. The tetras and otocats in my tank are all thriving. I’ve had the Cory’s for five months and within two days have lost three. Not sure what the issue is it seems to be a species only thing. Any insight on this?

 

[efirerobin]

My Cory’s are randomly dying this week, no signs of illness or anything, my water perimeters are all where they should be the temperature is set at 77. The tetras and otocats in my tank are all thriving. I’ve had the Cory’s for five months and within two days have lost three. Not sure what the issue is it seems to be a species only thing. Any insight on this?

To add on, I have done nothing different in the tank. no changes to anything and been keeping up with regular water changes and tank cleaning as I always have

 

[Colin_T]

Basic First Aid For Fish
Test the water for ammonia, nitrite, nitrate and pH. Post the results in numbers here.

Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.

Do a 75% water change and gravel clean the substrate every day for a week or until the problem is identified. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so any medication (if needed) will work more effectively on the fish.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.

Post clear pictures of the fish and one of the entire aquarium so we can check them for diseases.

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

Have you added anything to the tank in the 2 weeks before this started?
What symptoms do the fish have (if any)?

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?
Do you dechlorinate the new water before adding it to the aquarium?
Do you have separate containers and hoses specifically for the fish?

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

Do you have anything (soaps, moisturiser cream, hand sanitiser residue, grease, oil, perfume, etc) on your hands when working in the tank?
Does anyone smoke, paint or use aerosols in the room with the aquarium?

 

[efirerobin]

Basic First Aid For Fish
Test the water for ammonia, nitrite, nitrate and pH. Post the results in numbers here.

Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.

Do a 75% water change and gravel clean the substrate every day for a week or until the problem is identified. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so any medication (if needed) will work more effectively on the fish.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.

Post clear pictures of the fish and one of the entire aquarium so we can check them for diseases.

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

Have you added anything to the tank in the 2 weeks before this started?
What symptoms do the fish have (if any)?

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?
Do you dechlorinate the new water before adding it to the aquarium?
Do you have separate containers and hoses specifically for the fish?

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

Do you have anything (soaps, moisturiser cream, hand sanitiser residue, grease, oil, perfume, etc) on your hands when working in the tank?
Does anyone smoke, paint or use aerosols in the room with the aquarium?

Super helpful copy and paste.

 

[Lcc86]

Do you have any pictures of the affected fish? What is your water cleaning procedure?

 

[Colin_T]

Super helpful copy and paste.

Any chance you can answer the questions in the bottom half of post #3?
Reposted below

Have you added anything to the tank in the 2 weeks before this started?
What symptoms do the fish have (if any)?

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?
Do you dechlorinate the new water before adding it to the aquarium?
Do you have separate containers and hoses specifically for the fish?

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

Do you have anything (soaps, moisturiser cream, hand sanitiser residue, grease, oil, perfume, etc) on your hands when working in the tank?
Does anyone smoke, paint or use aerosols in the room with the aquarium?

 

[efirerobin]

Do you have any pictures of the affected fish? What is your water cleaning procedure?

I don’t have any pictures I remove the dead fish immediately when I see it but all my fish will look fine at night then I wake up in the morning and ones just dead. No symptoms like bloating, lethargy, all were eating fine.

I do about 1/4 water change every week to two weeks and vaccum the gravel every second water change to about half the water

 

[Lcc86]

Not sure how big the tank is but generally maintenance would involve at least a 50% (ideally more) water change each week. Try larger more regular water changes to see if that makes a difference.