I just got 20 Cardinal tetras. They are brand new in the tank and came right from the shipper since the LFS hadn't even put them in their store tanks yet. I know stress can cause a fish to loose color, but these guys are really pale. I barely see any red at all. Do they look okay? Do I just need to be more patient?
Are these Cardinal tetras okay?
- Thread starter BeckyCats
- Start date
I will be SO annoyed if they are neons.
I wouldn't worry at this stage. IF they are swimming relatively "normally," they will be fine. And while the photos are still pictures and not video, from their positioning I would say they are "normal." Cardinals are highly sensitive to water parameters, water quality, and being netted and changing environments. They very frequently are close to death when we get them (from the exporter to the store I mean), so what I see here is very encouraging. Many of us don't really understand the trauma a fish endures from collection to arriving in our tanks; it is truly amazing that any of them even make it alive. Which I guess only shows the resilience nature sometimes has. The red will brighten up.
[Edit: While I was typing, the suggestion was made they are neons, I can absolutely say they are not, they are cardinals. What I wrote below will help to explain.]
And speaking of that, it appears you have the Brazilian form of this fish. The species Paracheirodon axelrodi (cardinal tetra, sometimes called red neon in Europe) has a fairly wide distribution in South America. It is widespread in the Rio Negro basin to the north of the main Amazon River, which itself is a huge area, the third largest basin in Amazonia, covering an area larger than the size of France. It is the world's largest blackwater river. The other geographic home of this species is in the Upper Rio Orinoco basin in Colombia. There is a high mountain range separating these two basins, and it is believed the species was thus separated into two geographic locales when these mountains rose millions of years ago.
The Brazilian (southern) form is my favourite, being the most colourful. The red extends further under the belly than on the Colombian form, so there is more red and less white on the ventral surface. The blue "neon" lateral line on the Brazilian form extends to a point under the adipose fin, but ends anterior to this fin on the Colombian. The line is thus more straight and longer in appearance on the Brazilian form, giving the fish a longer and more slender profile than its chunkier Colombian form. From the photos, I believe you have the Brazilian form, and I would surmise these were direct imports from Brazil, likely from Manaus. [The Colombian form is more common as they are easier and less expensive to collect.] A few decades ago, 20 million cardinals were being exported from Manaus every year, about 80% of the total tropical fish exports from that city; even so, collectors noted that there were just as many cardinals in the habitat year after year, and to this day the fish is still widespread.
The great characin authority Dr. Jacques Gery suggested that the two variants might be distinct species, subspecies or simply geographic variants. Subsequent and more recent DNA cladistic analysis has shown they are the same single species with geographical external variants as I've described above.
To finish this off, there are four known species (only three of which are described, I'll come back to this) being P. axelrodi (cardinal), P. innesi (neon tetra) and P. simulans (false or green neon tetra). The cardinal is most closely related to P. simulans, differing by three chromosomes in their DNA, whereas the neon differs by ten (if memory serves me). It is not surprising that the Brazilian form of the cardinal is closer in appearance to the P. simulans. The fourth species was discovered by Heiko Bleher in 2006 in an extremely remote area; Heiko brought back a couple of specimens and DNA analysis has shown they are closest to the neon tetra, and their external colouration is closest to this fish. All of these four species, and no others yet discovered, have the characteristic iridescent blue/green line that contains pigment cells known as iridophores (or sometimes guanophores); these reflect light using plates of crystalline chemochromes made from guanine. In light, these generate iridescent colours due to the diffraction of light within the stacked plates. A truly beautiful genus of fish.
Byron.
[Edit: While I was typing, the suggestion was made they are neons, I can absolutely say they are not, they are cardinals. What I wrote below will help to explain.]
And speaking of that, it appears you have the Brazilian form of this fish. The species Paracheirodon axelrodi (cardinal tetra, sometimes called red neon in Europe) has a fairly wide distribution in South America. It is widespread in the Rio Negro basin to the north of the main Amazon River, which itself is a huge area, the third largest basin in Amazonia, covering an area larger than the size of France. It is the world's largest blackwater river. The other geographic home of this species is in the Upper Rio Orinoco basin in Colombia. There is a high mountain range separating these two basins, and it is believed the species was thus separated into two geographic locales when these mountains rose millions of years ago.
The Brazilian (southern) form is my favourite, being the most colourful. The red extends further under the belly than on the Colombian form, so there is more red and less white on the ventral surface. The blue "neon" lateral line on the Brazilian form extends to a point under the adipose fin, but ends anterior to this fin on the Colombian. The line is thus more straight and longer in appearance on the Brazilian form, giving the fish a longer and more slender profile than its chunkier Colombian form. From the photos, I believe you have the Brazilian form, and I would surmise these were direct imports from Brazil, likely from Manaus. [The Colombian form is more common as they are easier and less expensive to collect.] A few decades ago, 20 million cardinals were being exported from Manaus every year, about 80% of the total tropical fish exports from that city; even so, collectors noted that there were just as many cardinals in the habitat year after year, and to this day the fish is still widespread.
The great characin authority Dr. Jacques Gery suggested that the two variants might be distinct species, subspecies or simply geographic variants. Subsequent and more recent DNA cladistic analysis has shown they are the same single species with geographical external variants as I've described above.
To finish this off, there are four known species (only three of which are described, I'll come back to this) being P. axelrodi (cardinal), P. innesi (neon tetra) and P. simulans (false or green neon tetra). The cardinal is most closely related to P. simulans, differing by three chromosomes in their DNA, whereas the neon differs by ten (if memory serves me). It is not surprising that the Brazilian form of the cardinal is closer in appearance to the P. simulans. The fourth species was discovered by Heiko Bleher in 2006 in an extremely remote area; Heiko brought back a couple of specimens and DNA analysis has shown they are closest to the neon tetra, and their external colouration is closest to this fish. All of these four species, and no others yet discovered, have the characteristic iridescent blue/green line that contains pigment cells known as iridophores (or sometimes guanophores); these reflect light using plates of crystalline chemochromes made from guanine. In light, these generate iridescent colours due to the diffraction of light within the stacked plates. A truly beautiful genus of fish.
Byron.
I specifically asked if they were neons and was told no. I wonder how long it takes for their color to come up. The red should tell us if it ever shows, right? Okay, first: I hope the fish are okay; second: these better actually be cardinals! Neons prefer slightly cooler temps than what I keep for my pearl gouramis, which is why I chose cardinals.
Ugh! How long before they color up? I'm freaking out now.
Ugh! How long before they color up? I'm freaking out now.
OMG, heart attack city!! Our posts were done at almost the same time I think so I didn't see it before adding my last. Thank you for putting my mind to rest. I was freaking out. If they were neons, I would have had to figure out if it is worse for them to be netted and returned to the store or to live in slightly higher temps than is their ideal.
I happen to know that this store gets its fish shipments in on Thursdays, and the manager told me she had ordered Cardinals, so when they came she would call me right away before they put them in the store tanks. This way, I was thinking they would have one less traumatic transition to endure. So far, no casualties, no odd swimming. Just very, very, pale.
I have generally found that overnight will be sufficient, though I don't know what these fish were subjected to and if it was really traumatic it might take them longer. But when I see new fish swimming around, exploring their surroundings, I consider that to be the big step forward and the colouring up will come.
I found one up in the water sprite breathing super fast. I don't suppose there's anything I can do to help the little critter?
Hopefully the others will make it.
Other than leaving it alone, no. There is always the possibility that one of them (or even more) were internally injured during the netting, wherever. There is also the possibility that all the stress was too much for this individual fish, and severe stress causes internal issues we can't see nor treat. If it is a water parameter/quality issue, it would affect more of them at the same time.
As I've said, this is a very sensitive species. I have a group of its close relative, Parachierodon simulans, in my 40g. When I set this tank up last May, and moved the shoal from the 29g, two of the fish appeared near death, even so far as lying on the substrate in a corner. I left them alone, and they recovered overnight. I still have all the fish in the shoal today. But they do not like being netted and moved.
I am so disappointed so far. This is the morning of their forth day, and I only see 9 left. There were 13 when I went to bed last night. I can't get closer to the tank right now because I have a case of C.O.L. syndrome (cat on lap) and he's 18 years old, and he's purring, so, well, you can see why I can't get up right now. Anyway, I only see 9 of the 20 I put in on Thursday. 2 of the 9 aren't with the group either, so that worries me. There has still been no sign of the red stripe beyond what shows in the pictures above.
Did I mention that they are very small? I have never had cardinals but I have seen them in stores for sale before and they are usually larger. If these are very young, could that be why there is no red and/or why so many are dying?
The other thing is that as of last night, there were 13 left. I found 5 of the bodies, but 2 are completely missing. How can a whole fish just disappear?
The likely answer to that makes me think I need to set up a quarantine tank. Is 10 gallons sufficient or does it need to be 20? How do I keep it cycled in between use? I just don't like the idea of the fish going through one additional move (from store to quarantine, then quarantine to main tank).
Sorry, one other thing. Was it a mistake to add all 20 at one time? I have monitoring water quality 3 to 4 times a day since adding them, and nothing is changing. This tank has been fully set up and cycled for almost a year, so it didn't seem like an issue, but I want to know about everything I can do differently in the future to prevent this level of loss. The store employee said they lose a lot of tetras especially cardinals, so maybe this was just a weak group?
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