armadillo

Hi everyone.

I was at a fish/aquarium fair yesterday, and talked to a cory breeder about the trouble I'm having keeping panda corys alive for more than a few weeks.

He told me that panda corys, when stressed, release an alarm substance which is actually poisonous to them in high concentrations (i.e. more likely in an enclosed environment).

He told me that he never kept panda corys without regularly refreshed activated carbon. He even had activated carbon grains in the transport bag.

I tried to find articles corroborating this on the internet but came up with nothing, so this is unreferenced. Still, I thought I'd let you know in case you were having the same troubles. I for one am going to give it a go with the AC.

Barbrella

I think there's a couple reasons why Pandas often do not survive in aquariums.

One is that they prefer a much cooler temperature than most tropicals. 72 degrees is ideal for them.

Also, they are extremely intolerant (much more so than other species) of water that is not kept pristine and will rapidly succumb to infection from stress and disease if any toxins are present.

So maybe their rapid demise in too-warm tanks containing nitrites etc., is where the "poisonous substance" idea comes from.

armadillo

I think there might be some truth to it. Why not, hey? It's not like they would be the only animal using alarm pheromones when stressed. Gazillions do it. It would be surprising that nothing's come up in my internet searches, and that other corys don't have this, but it wouldn't be the most surprising thing I've ever heard.

Would AC absorbe excess nitrate/nitrite/ammonia?

Barbrella

Yes, many animals give off substances that may be toxic, but I've never heard of one giving off any that poison only themselves and not any other creatures nearby. Not a good nature's plan for survival of the species!

Breeders often have tricks and tips that are passed around and handed down, and they work but often not for the reasons the breeders think they do.

If the person you talked to thinks there is some noxious substance being released by pandas, he no doubt makes sure to keep the water extra clean and that would contribute to the survival of his fish, with or without AC.

Pandas in petstores have usually gone through several trips, stuck in small bags of water that get dirty, so why don't they all die en route, trapped in small bags while releasing toxic substances?

My Pandas died too, seemingly for no reason. My search for answers resulted in the conclusion that they arrive in our homes from the petstore in an already weakened condition from the stress of travel/dirty water, and easily succumb to infection causing their eventual deaths.

armadillo

Well I agree with you. I think it's a stretch, but I'll argue here for argument's sake (meaning there's the teenest tiniest possibility that it's completely true):

[quote=Barbrella;333818]Yes, many animals give off substances that may be toxic, but I've never heard of one giving off any that poison only themselves and not any other creatures nearby. Not a good nature's plan for survival of the species![/Barbrella]

In nature, they're not in a confined space, so the substance would only be toxic in high concentration. That could explain that.

Pandas are more sensitive than most many other corys to any substance: nitrate, nitrite, etc. So that would explain why they're the only ones to go. When they are dead, they no longer release the substances, explaining why the other fish don't go with them.

To really stretch my imagination, you could even extrapolate that, as the alarm substance is designed as communication among panda corys, it is on the contrary a very good design to have them more sensitive to the substance than other fish. Their senses would be geared to pick up that substance over and above other chemicals in the water.

Sooo true. I re-iterate this: I was not able to corroborate this, so take it with a pinch of salt.

We can't use that as an argument either way: it doesn't imply, nor reject, the influence of AC on panda survival. We don't know whether the breeder experimented with clean water/AC; dirty water/AC; clean water/no AC and dirty water/no AC.

That's a very good point, but again, don't a lot of pandas have a very low survival rate after arriving home? This could explain that.

I also could never really find a satisfactory explanation, but that doesn't mean that one that hasn't come from the internet but from word of mouth is invalid.

Still, I don't really know whether it's true, and if so, to what specific extent, but am giving it a go and I've started keeping pandas again. I'll let you know how it goes.