I tried for several years to disprove this "myth". Year after year I made improvements and changed things. My rays seemed to do fine, my other Characins seemed to do fine. We all tried to figure it out, and it seemed we failed. I failed to disprove the myth, so is it really a myth? Apparently it still is. I find it kind of disrespectfull to tell someone who tried so hard are put forth so much effort that they simply don't know what they're talking about.....
You say that there's hundreds or thousands of these fish in posession of the people that don't care about the internet. My view is there's hundreds or thousands killed every year cause people have no clue what they're getting into with these fish. They buy them cheap, grow them up, and sell them. Year after year people can't provide proof that they do well and grow big in captivity, and I'm just supposed to believe there's plenty out there? Yeah, maybe my opinion is flawed, but surely someone who has a giant Armatus knows someone who is on the internet, funny there's so many fishing pics out there, and pics floating around the internet of the big ones over seas, yet we can't cough up a few out of all the hobbyists on this site? I bet there was hundreds of MFK members that bought Armatus every year, yet how many hit 2' ++? Did all those MFK members sell thiers to people without the internet? That captive care guide sticky we wrote was done because of the crazy amount of care questions always popping up in this section of the forum by memebers of this site who had Armatus and the internet. Obviously there were lots of them out there. I see no reason why there's lots of pics of juvies and no adults.
Nobody likes a negative nancy, so I understand that being the debbie downer here could rub people the wrong way, and I apologize for that. Believe me nobody wants to figure this out more then me, but the first step in solving any problem is verifying or duplicating it. If we all continue to shroud ourselves in a bubble of reality where Payara do well in captivity then it's gonna be pretty hard to move forward....
You'd be argumentative to if you had an opinion with several years of experience to back it up that is viewed as a "myth" rather then actual real world experience.
I'm not trying to be the bearer of bad news, or crap in everyones cheerios, but all the evidence that there's a problem with our care for these things is and has been festering throughout this site for years and years, all you have to do is search for it or remember it if you were around for it.
I can certainly understand your point of view in regards to these fish in light of your experience. Given the circumstances that you
appear to be describing, I'm concluding that you tried to keep your fish in a 'monster' community tank? Or did you do cater the tank to their needs? edit- by cater to their needs, I mean keep the fish in a large tank by its self or with other current loving characins in a tank with a ridiculous amount of current.
I have a feeling that your probably right in regards to these fish having a hard time reaching maturity due to the care provided by the owners. I feel its probably fair to say that Americans on the whole tend to be not as committed to things as our Asian counterparts, be it in fishkeeping or anything else. I feel that there are likely more large fish in east Asia due to the dedication of their keepers. I find it hard to believe that fish imported to America are more likely to die than those imported to east Asia. I've noticed that a lot of the big payara and tigerfish in Asian tanks have only those fish with a few bottom dwellers that are compatible.
I've also noticed that the vast majority of American keepers who attempt to introduce these fish to their tanks have a wild assortment of fish. The American keepers (in general, not everyone) keep their payara in general community tank conditions on a monster scale. Few of us go out of the way to simulate the payara's natural powerful riverine habitat, as most 'normal' aquarium fish would be quite stressed by this environment. On the other side of that coin, I find it likely that payara are stressed by the lack of a riverine environment.
This is why when I give advice to people interested in the silver tooth fish that in order to be successful, they need to cater the tank to the needs of the fish.
Part of the reason I believe you have had success with Rhaphiodon, and I'll admit that this is conjecture without knowing your exact setup, is because Rhaphs are not riverine. They are normally found in open water of lakes or impoundments, where as Hydrolycus and Cynodon prefer waters with powerful currents. If a Rhaph was kept in a 'normal' aquarium setting, it would stand to reason that they would thrive where as the other genera would struggle to survive or die.
A final point to consider. I feel that a 15-18 inch armatus is probably close to or at maturity. I feel this is evidenced by the fact that they tend to grow very quickly to this point and then slow down dramatically. It seems reasonable that if the fish is mature at 18 months to two years old at about 18 inches long, it would grow slowly past that point. The four footers we see people catching while fishing are likely very old fish, and getting a domesticated one to four feet, three feet or even thirty inches would probably take a very, very long time. Again, I've not seen anything in the journals that indicates that there is an age study for the members of Cynodontidae, so this is all conjecture until we see the results of further studies.
I'm interested to know exactly what kinds of setups you tried with your payaras over the years.