Sudden Cory Death?

[jourdy288]

On the 29th I bought an albino bronze cory, about 1.5 inches. On Sunday, the 30th, he was just fine. But on Monday, he had died. He had red marks on his left and right side, near the head. I was guessing my bright pink zebra danio, Shirley, was to blame. She is very aggressive, and shoves all the fish around. But what else could cause this? I tested my water, the nitrates were at 20, average, nitrites were 0, so any other factors?

 

[jourdy288]

Aww, a platy (not a newly purchased one) died yesterday.

 

[Inchworm]

Hi jourdy288

The most common thing to kill a cory is a bacterial infection and this must always be considered when a newly added one dies. Do you have more of them in the tank?

Bacterial infections can spread easily, so be prepared to do extra water changes and medicate if your fish continue to have problems.

There are always likely to be some harmful bacteria in a tank, but it's usually only when a fish is stressed that it weakens and becomes sick. This is often the result of such things as overfeeding, overcrowding, high nitrates or nitrites, rapid temperature rises, low oxygen level in the water. Exposure to these conditions can happen during shipping and while in the lfs too, as well as in your home.

Make sure your bottom is well vacuumed and that they aren't being over fed. If the temperature is above 75 degrees F., lower it a bit. You might also want to raise the oxygen level by adding an airstone to cause more surface movement. These things will make the environment less hospitable for the bacteria.

If you had your country of origin listed in your profile I would try to suggest a medication that would help. Perhaps you should ask what your lfs recommends.

 

[jourdy288]

Hi jourdy288

The most common thing to kill a cory is a bacterial infection and this must always be considered when a newly added one dies. Do you have more of them in the tank?

Bacterial infections can spread easily, so be prepared to do extra water changes and medicate if your fish continue to have problems.

There are always likely to be some harmful bacteria in a tank, but it's usually only when a fish is stressed that it weakens and becomes sick. This is often the result of such things as overfeeding, overcrowding, high nitrates or nitrites, rapid temperature rises, low oxygen level in the water. Exposure to these conditions can happen during shipping and while in the lfs too, as well as in your home.

Make sure your bottom is well vacuumed and that they aren't being over fed. If the temperature is above 75 degrees F., lower it a bit. You might also want to raise the oxygen level by adding an airstone to cause more surface movement. These things will make the environment less hospitable for the bacteria.

If you had your country of origin listed in your profile I would try to suggest a medication that would help. Perhaps you should ask what your lfs recommends.

I'm in the states. I only have one cory, had him a while, and he is healthy, so it must have been newly brought to the store. Must have been stress. Thank you.