Lost Two Cory Cats

[Shady Munky]

Hello,
 
I came home from work today and my two Cory cats were dead.  These cats were near 20 years old, and they died on the same day.   The tank is well established and has been running for over 4 years.  I've tested my water and things seem fine.  Temperature is ~77, I had just done a 35% water change on Sunday.  I introduced two new Rainbowfish and five neon tetras last week.  None of the other fish in the tank seem to be having any issues.  I use Melafix in the tank after a water change, but I have always done this and it has never bothered them before.  I'm concerned that something I'm not thinking about is going on.  I'd like to get new Cory Cats but I want to make sure I'm not putting new fish into a bad situation.  Any thoughts or comments are welcome, and I appreciate your time.
 
Thanks,
Marc
 
Tank Type: 35 GAL. Hexagon freshwater with Fluval 206 
Fish: 
8 Rainbows
7 Neons 
5 Bloodfin tetras
1 Pleco
 

 

[Robbo85]

wow 20 years is quite long for a cory, maybe not unusually so but a quick goggle of cory lifespan brings really varied answers from 4-8 years 6-12 years and some saying up to 20 years with the oldest recorded being 32 years. what type of cories are they?
I would say it sounds just like old age but its the two going at the same time that's the issue.
 
Have you tested the water? could of the new additions caused an increase in nitrates which younger fish could of dealt with but just pushed the olds guys over?

 

[Akasha72]

I'm inclined to agree with Robbo, at near 20 years old they had a very good life. I believe the average is around 10 years. I currently have 3 that has been with me since the beginning of my fish keeping journey which is around 7 years ago. They still play like the youngsters

 

[Seanthebusdriver]

If everything else is happy and your water supply hasn't changed it sounds like just an unfortunate coincidence to me. All respect on the age of the Corys, are you sure the 'school hamster' trick hasn't been played here

.

 

[DoubleDutch]

Most Cory-species can easily get 20 years and older. I believe Ian Fuller (Coryguru nr 1) mentioned having had a Sterbai of 42 years.
One thing is sure : If two fish die of old age at the same day you should buy a lotery-ticket immediately. Very unliky !

 

[Akasha72]

could it be that one died and the other died from stress? I spend my life watching my cories and the way they interact with each other and they really are a little family. They hang out together, they feed together, they all play together too ... if there was only two and one died I would be willing to believe the other died from a broken heart and stress if losing it's friend

 

[DoubleDutch]

could it be that one died and the other died from stress? I spend my life watching my cories and the way they interact with each other and they really are a little family. They hang out together, they feed together, they all play together too ... if there was only two and one died I would be willing to believe the other died from a broken heart and stress if losing it's friend

It definitely can die of loneliness, but not at the same day

 

[Shady Munky]

I bought them for my mom when I was 18, she passed them to my brother, and four years ago he passed them back to me.  I think adding the new fish has done something though.  I'm going to take a sample in.  My Nitrates, nitrites, and ammonia levels look just fine, but something must be awry.  I had changed the heater on Sunday too, but temps look to be holding fine.  I've never run an air stone in my tanks.  What are your thoughts on low oxygen levels?  If I had too much water and the pump outlet wasn't causing a surface disturbance could the oxygen levels dropped too much for bottom fish? 

 

[Akasha72]

the best way to check if cories are getting enough oxygen is to watch them. It's normal for cories to shoot up to the surface for a gulp of air but if they are doing it continually then they're not getting enough oxygen.
 
You mention that all water stat's are 'fine' ... can you please define 'fine' with actual number values - that way we can have a better look at what might be happening

 

[Shady Munky]

Natrate: 2
Nitrite: 0
PH: 7.2
KH: 70
GH: 80
Ammonia: .1
 
I hope to get some more info later on today.  The rest of the population is still doing well.  Temp is holding nicely around 77F.  I just have an API test kit so I'm sure the local store will have something far more detailed than I do.

 

[Akasha72]

ammonia should be zero. Cories tend to be sensitive to ammonia and nitrite ... my best guess would be that the ammonia reading was the cause for their death