Roseline shark lifespan?

[MultipleTankSyndrome]

The often cited 4 to 5 year lifespan of roseline sharks seems on the short side to me. Perhaps I'm not in a position to comment on it since I have yet to keep them, but still.
Is there anyone on here who has kept them 4-5 years (or more) and can vouch (or not, if you kept them longer) for the accuracy of that?

 

[RD.]

Most lifespans (including humans) are based on averages, so a few folks that have kept this species longer than 4-5 yrs, or less than 4-5 yrs, statistically speaking wont amount to anything significant. My hunch is that the vast majority of this species of fish never reach 5 years, in a hobbyists tank. Not MFK hobbyists, but hobbyists in general. As an example, discus are known to live 10+ yrs, but according to many discus keepers the average lifespan of domestic strains of discus is 3-5 yrs.

 

[jjohnwm]

Funny that you should mention this; I have only very recently begun considering this species for addition to one of my "temperate" tanks, kept at somewhat lower temperatures than typical "tropical" fish. Apparently, the roseline's habitat experiences temps down to 60F and below on a regular basis.

I have a sneaking suspicion that perhaps this species tends to be shorter-lived in a heated tropical tank than it would be in nature, or in an aquarium geared more towards its natural temperature range. Perhaps it requires seasonal variations, like many cichlids seem to, in order to achieve ideal conditioning and maximum lifespan.

I have an innate distrust of many of the websites that spew endless lists of "care guides" and other supposedly authoritative data on aquarium fish (and most other topics, to be honest). Much of it seems to be written by individuals with literally no personal experience with the fish in question; they parrot and repeat the same old same old, often so blatantly that entire sentences and paragraphs are lifted and repeated word for word.

I want info from sources whose credentials include actual experience. Reading other websites and repeating exactly what they say...does not equate to credibility, nor does it make one an "expert" worth listening to.

 

[MultipleTankSyndrome]

Interesting consideration jjohnwm. Valuable food for thought, and it also looks like I made the thread at just the right time, lol.

Between having made this thread and now I had done some searching and found esoxlucius say that he had some for 10 years.
I'd be interested to know, if he can remember, what temperature they were kept at. Always tropical? Always temperate? Fluctuating between the 2 to match seasons?

A much longer reported case than 4-5 years, and we may be able too see what temperature it happened at too to test jjohnwm's guess. Absolutely perfect for the thread.

 

[MultipleTankSyndrome]

And here is the link to that: https://www.monsterfishkeepers.com/forums/threads/denison-centric-restock.741357/post-8354338

 

[RD.]

What he said was;

i've had specimens for around 10 years.

Was it actually 10, or 8-9? Also, how many, vs those that didn't reach that age? All interesting data, that at least informs folks that some may reach that age, but still not exactly verification that 4-5 yrs is way off the mark, for an average lifespan. I've seen adult Ampholophus that have reached 15 yrs or more, a couple 17-18 yrs, yet if one was to gauge the average lifespan in captivity, 8-10 would probably be more realistic.

The way things currently are in the world, I'm beginning to hope that my lifespan is below the national average. ?

 

[jjohnwm]

The term "average" can be very misleading in terms of using it to determine how long one can expect an animal to live. The more delicate the animal, or the more demanding its requirements are, the shorter the average will be...but that's simply because most of them don't survive nearly as long in captivity as they should/would if maintained optimally.

I recall reading a study of the wild turkey in Ontario, which stated that the average age a turkey survived in the province worked out to something measured in only a few days...because so many young birds were killed and eaten within the first few days after they hatched that the average was skewed downwards that far. They even stated that if they had calculated the average lifespan by considering the life to begin when the egg was laid (rather than actually hatched)...the average lifespan would have been measured in mere seconds, because so many eggs were predated before even hatching. Interesting numbers, but what do they really tell about how long a turkey will live? Not much!

Regarding Esox's fish, I am certain that when he says he kept a fish for X years, that means he had that specimen for that long. But...I know one guy back in Ontario who will authoritatively state that he has kept the XYZ species for a decade...whereas I personally know that he bought them, quickly killed them, bought some more, tortured those to death, bought some more...you get the picture.

 

[MultipleTankSyndrome]

You make a good point on the around leaving room for interpretation. But I will say that after reading your post and getting a flashback in memory to another*, I find average lifespan of fish is not a very useful statistic.
The reason for this is that while there are certainly fish that die from old age in captivity, several also die from factors such as disease, bad water quality, lapses in/improper husbandry, power outages, or jumping out of the tank. Meaning that these factors make the average unrepresentative of the age a fish can live to before dying of old age.

*This flashback was to a point made by jjohnwm on how outside factors throw average lifespans out of whack but with turkeys. I see I was ninja'd to him about it, he replied just as I was typing this!

 

[jjohnwm]

Great minds...

Yeah, I type so slowly that a lot can happen in a thread before I finish. Didn't realize I had mentioned the turkey thing before, but not surprising; it's one of my favourite examples of accurate information that can be presented in such a way that it means...virtually nothing!

 

[esoxlucius]

Lol. If I'd have known that the great age of my Dennison's would come under such scrutiny I would have been more clear as to their exact age, rather than just round it off to just 10.

RD. is correct. My original, "I've had specimens for AROUND 10 years" quote was in fact more like 8 years to be fair. I can be confident of the 8 because I remember when the tank was set up, and due to circumstances later on, I also remember when that tank was broke down. This was all in my first stint in the hobby many years ago.

Basically, I bought about ten, a couple died early on and then the other eight or so grew, matured and just lived their lives. The rest started dying off one at a time around the 6 year mark. Around the 8 year mark I had to break the tank down (really bad relationship problems). At this point I only had a couple left and due to breaking the tank down and being in a bad place emotionally and mentally I donated my community fish to a neighbour.

Soon after that I heard that the fish I'd donated had died! All of them, not just my two 8 year old dennisons. I still feel bad to this day regarding those donated fish.

Regarding the seasonal low temps for this species which M MultipleTankSyndrome alluded to. When I had those fish all those years ago, don't forget, this was in a bygone age, no fingertip research was available so to be honest I never even knew back then that they can benefit from cooler temps. Mine were always kept at your bog standard tropical temps.

And if my circumstances at the time would have allowed me to keep those fish, the burning question is, would I have squeezed another couple of years out of my remaining two to achieve that magical 10 year figure? Now that would have been a thing.