Cardinal Tetras. Do you have problems or is it just me?

[undbulsu]

I am trying to build up a school of about 20 cardinal tetras for an upcoming discus tank. I have had cardinals before, and no matter where I purchase them from I seem to have about a 25% die off before I even get them out of quarantine. I am following all the rules for acclimation, even to the point of setting up a drip system to slowly change the water.
And it always seems to be the more "healthy" appearing fish. Brighter colors, deeper red, etc. Is is hormones? Are they injected? Do they just not ship well? Any tips?

[lmw80]

Cardinal tetras are very sensitive fish. I know of many people that have the same problem you are having.

[Tiffi]

Most, if not all Cardinals are imported from the wild and not captive breed like neon tetras. As wild caught fish they are very sensitive. I don't know though why all your "healthy" appearing ones die off first.

Anyway, many people have the same problem as you have. And 25% death rate is pretty low.

Nevertheless, if you switch to neon tetras you won't have much more luck neither, because many of them have the neon tetra disease and die off quickly as well!

Further, you have to be careful keeping cardinals and discus in one tank!! The cardinals can quickly end up as a snack!! And for that, all the hassle with getting a surviving and large enough school would be just too much IMO.

[tropicfishman]

they do die off quickly, I don't think anyone knows why, its just one of those things

[joannde]

ditto for neon tetras - they're just very very sensitive to changes I guess.

[shawmutt]

They are very delicate fish. They require a tank that has been up and running at least 3 months, preferably 6, with very low nitrates (and of course no ammonia or nitrites). Since they are caught in the wild, they need very soft, acid water to match their natural habitat. If they are tightly shoaling after a couple day "break-in" period they are too stressed and won't last long. I found that a solid black background, java fern, plenty of hiding spaces, and tea-water brown with tannins is ideal for the little buggers (with the added benefit that these surroundings really bring out the color. They need to be bought from reputable dealers who understand them. I got all mine from a lfs called Rick's Pets, and they lived for a good time. I had a steady population for about 8 months, and then put hatchets in which introduced ich and nuked the tank.

Another option is to look for tank raised cardinals. They are usually advertised as such, and cost more, but are hardier.

As far as discus and cardinals, Rick's Pets has a beautiful discus tank set up with a school of cardinals, and they are fine.

Google "Amazon black water" and "Rio Negro" and you'll find a wealth of information. I have a picture of my tank setup in my gallery (it's the dark one with the skull).