# Tank Raised Cardinal Tetra's in hard water?



## amazon21 (Jun 28, 2010)

Would tank raised Cardinal Tetra's go through the same calcium buildup problems that happens when wild caught Cardinals are put into hard water. I've have a pH of 7.2, and a total hardness of about 120 ppm, and am considering adding Cardinals since my LFS sells tank raised ones.


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## Byron (Mar 7, 2009)

This is an interesting question. I have had tank-raised cardinals and wild cardinals. The wild are better and preferable. They are more colourful and so far tend to be more resilient to various things. From my experience I would never buy tank-raised cardinals again. But then, I always buy wild caught fish if I can, for much the same reasons. Plus it supports the local economy in the tropic regions and helps them to sustain the environment. But I can't get into all that here.

Back to the issue, it would also depend upon the water the fish were spawned and then raised in. I suspect it is very soft. So far, these fish have not spawned in hard water, or if they have, the eggs will not fertilize or hatch. Due to the hardness in the water. So to my thinking, tank-raised in this case means in soft acidic water. I will graciously bow to another authority on this, though I find it very difficult to fathom that nature can be side-stepped so significantly as this would suggest. I know the tank-raised cardinals regularly available where I live are raised in our very soft water.

Byron.


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## amazon21 (Jun 28, 2010)

I've done a little research about it, and from what I've heard, it seems that tank raised cardinals adapt better to hard water than wild caught ones. Of course, I havn't found any studies or experts explaining this topic, just other fish profiles in other sites and forum posts. If it is true that tank raised cardinals adapt better to hard water, I would guess it is because tank raised Cardinals come to the pet store young, which makes it easier for them to adapt to hard water while the wild caught Cardinals which are adults. Your explanation makes a lot of sense as well. I wasn't sure if "adapt" also referred to the calcium problem, but as you said nature probably can't be side-stepped like that, so I'm guessing a tank-raised cardinal would have a short lifespan in hard water just like a wild caught cardinal tetra.


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## Byron (Mar 7, 2009)

amazon21 said:


> I've done a little research about it, and from what I've heard, it seems that tank raised cardinals adapt better to hard water than wild caught ones. Of course, I havn't found any studies or experts explaining this topic, just other fish profiles in other sites and forum posts. If it is true that tank raised cardinals adapt better to hard water, I would guess it is because tank raised Cardinals come to the pet store young, which makes it easier for them to adapt to hard water while the wild caught Cardinals which are adults. Your explanation makes a lot of sense as well. I wasn't sure if "adapt" also referred to the calcium problem, but as you said nature probably can't be side-stepped like that, so I'm guessing a tank-raised cardinal would have a short lifespan in hard water just like a wild caught cardinal tetra.


The age of the fish is a valid point but I think may not apply nonetheless. Most wild caught fish are very young, the prime collection time is a couple months post hatching and this is largely regulated by law now to ensure the wild stock is not exterminated by over-collection and to protect the spawning period. In my local store that regularly has both wild and tank-raised cardinals, they are exactly the same size, about 1/2 to 3/4 of an inch.

Do you have links to those sites where it suggests tank raised cardinals can adapt to harder water? I'd like to pursue this. I frankly find it less than believable. Adaptation in such fish means the fish's physiology is somehow being altered to manage in different parameters. And while this is certainly possible--after all, evolution is just this very thing, all species on earth have evolved to suit their present environment, and the cardinals have evolved over millions of years to require very soft acidic water--achieving this by raising them in a tank of soft water does not seem probable. It would presumably require several generations of increasingly harder water, and the fish would either evolve or die out. If you can provide these links, I would be interested, and might even pose the question to someone like Dr. Stanley Weitzman.

Byron.


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## amazon21 (Jun 28, 2010)

Byron said:


> The age of the fish is a valid point but I think may not apply nonetheless. Most wild caught fish are very young, the prime collection time is a couple months post hatching and this is largely regulated by law now to ensure the wild stock is not exterminated by over-collection and to protect the spawning period. In my local store that regularly has both wild and tank-raised cardinals, they are exactly the same size, about 1/2 to 3/4 of an inch.
> 
> Do you have links to those sites where it suggests tank raised cardinals can adapt to harder water? I'd like to pursue this. I frankly find it less than believable. Adaptation in such fish means the fish's physiology is somehow being altered to manage in different parameters. And while this is certainly possible--after all, evolution is just this very thing, all species on earth have evolved to suit their present environment, and the cardinals have evolved over millions of years to require very soft acidic water--achieving this by raising them in a tank of soft water does not seem probable. It would presumably require several generations of increasingly harder water, and the fish would either evolve or die out. If you can provide these links, I would be interested, and might even pose the question to someone like Dr. Stanley Weitzman.
> 
> Byron.


That's the problem. I don't have any sources that are credible enough to believe. All I have found about the topic is a lot of forum posts where people suggest that tank raised cardinals are hardier and can stand alkaline conditions better than wild caught ones. Even the wikipedia page on Cardinal Tetras states "Captive-bred cardinals tend to adapt to hard water better than wild-caught cardinals." Of course none of them explain why. I have even seen a post where somebody claims to have spawned Cardinals in a pH of mid-7 and a gH higher than 120, although I find this very unlikely. From what you've said, I'm starting to think it must be some kind of fish keeping myth.


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