Why Are All My Cories Dying?

[ghostchoir]

My tank has been setup for around 6 months now. I have had my julli cories for all of that time and have not had a single death. My julli group has a total of 6 cories, and there are some other cory groups that they seem to play with too.

My tank is 125litres. There are only peaceful fish and nothing that I have ever seen attack the cories. Nitrite is 0, ammonia is 0, nitrate is the lowest on my chart. I change the water every week and it's kept at 24 degrees. I haven't added any new fish in at least a month.

However, I woke up this morning to feed them and found 4 of them dead I took them all out and buried them. I've just checked on them again and another has died! The one left doesn't seem to be sick at all, he's very energetic and is happily hanging upside down cleaning plants - but so were all the others.

Why have all my jullis just suddenly died?

I won't be able to get more jullis for around two weeks as I'm going on holiday and the shop I get them from is not open until I go away, naturally. Will my remaining one be okay without his shoal?

 

[ArauraDiscus]

WHat are your water perameters. Please post the results asap. This isn't normal at all.

 

[ghostchoir]

Listed above but:

Nitrite: 0
Ammonia: 0
Nitrate: lowest on the chart
pH: 7

 

[ArauraDiscus]

oops sorry, Fish Tuberculosus is the number one unexplained fish death cause. It affects the insides and often destroys organs before you know whats going on. SOmetimes it also damages the spine making some oddly shaped fish. It's very difficult to treat, but it's a bacteria so bacterial meds may help. Also since they are cories, they are constantly rooting through the gravel where fish waste is. Eating other infected fishes poop, or eating dead fish is the number one cause of a spread of Fish TB.

 

[ghostchoir]

But if that were the case, wouldn't some of the other fish be dying? It's only been the cories, and all of them died whilst looking perfectly natural and after behaving quite happily throughout the day. And it's only been the jullis, the other cories are fine and so far none of my other fish have shown any problems either.

 

[*Fishkies*]

What is your stocking list for your tank?

 

[Amunet]

Was anything sparyed around the tank? Guess the other fish would be dying as well though.
Was their food source exposed to anything? Like maybe you didn't rinse your hands off thoroughly so some soap got on their food when you fed them?
Does anyone else do anything to the tank?

I'm just throwing out ideas.
So sorry you've lost so many

 

[ArauraDiscus]

With fish tuberculosus, it is sometimes only transmittible through fecies. The other fish may not be rooting through the gravel like the cories, and only the cories are the ones ingesting fish poop. Tuberculosus isn't highly contagious like ich normally.

 

[Christine1014]

Corries are pretty particular about their substrate conditions, I've heard. There are some types of corries that should really only be kept with sand rather than gravel, and for the varieties than can be kept with gravel, it needs to be really clean - gravel vacs every week, for sure. But if all that is okay, I'm really not sure... maybe buy your next ones from a different store and see if you have better luck?