Survey: Life span of marine, ornamental fish in captivity

A

Agathos

New member
I have made a new survey that is better designed to reveal lifespans of our fishes. In this survey I ask you to list the number of years your fish lived in your tank before dying. Hence, only diseased fish is to be listed and only the time they lived in your tank. Please do not guess how old they were when they were introduced to your tank, or how long they had been in someone else's tank. I only want to know their time in your tank.

Here is the link to the survey:
http://www.kwiksurveys.com/online-survey.php?surveyID=IKINMM_67142847

Please participate since the value of this survey and the strength of the data is directly correlated to the number of attendees. Thanks!
 
cool! I replied to this as well
would it be possible to see the results, as for your first version, it showed the results when we finished the survey, but not this one...

cheers,
sabine
 
Only diseased fish??

What's your goal here? What purpose is it going to serve?

Not bashing, just trying to understand what you're trying to do.
 
Big E said:
Only diseased fish??

What's your goal here? What purpose is it going to serve?

Not bashing, just trying to understand what you're trying to do.
Click to expand...

I am trying to gather data on the average time different fish species live in our tanks. In my opinion there is not much information on lifespan of captive marine, ornamental fishes to be found, and I believe such information is interesting because it provides us with data on the difficulty of different species as well as some suggestion on their longevity. By looking at such data it is easier for both experienced and inexperienced aquarists to choose fish that with high probability will survive long in their care. If some fishes are notoriously hard to keep alive this data could give us an incentive to not buy them from the LFS's. It is also not apparent to many aquarists that different species have very different lifespans in nature (and hence in captivity, too) -- e.g. clownfish live for 15+ years while cardinals only for a few years -- and these differences would also be reflected in the data and could be of value when we plan our next tank additions. So to summarize I believe these data could be interesting to many of us for many different reasons.

And again, the value of this survey is directly related to how many participates, so I urge people to take the moment to add their experiences. The survey is of course completely anonymous and the data will not be used in any other context (at least from my side) than to inform people here on RC as well as on other forums for marine aquarium hobbyists.
 
auem said:
i think this thread from december will help you a lot...

http://reefcentral.com/forums/showthread.php?t=1943141&highlight=oldest+fish+in+your+tank
Click to expand...

Thanks! It doesn't really help to answer all questions raised in the survey but it is definitely interesting.

snorvich said:
Again, the results will not have scientific validity but they may prove interesting to some.
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Not that I am aiming for scientific validity, but out of curiosity, what disqualifies this study from being scientifically valid if we end up with enough participants to make the data statistically significant?
 
Your sample size (number of respondents relative to population), your sample selection (those that are on RC who choose to respond rather than random selection), your sample source validity (only those on RC) for starters. If you are simply looking for guidelines, no problem. If you are trying to infer population values from this sample, there is no real validity. But I am sure it will be interesting to some.
 
snorvich said:
Your sample size (number of respondents relative to population), your sample selection (those that are on RC who choose to respond rather than random selection), your sample source validity (only those on RC) for starters. If you are simply looking for guidelines, no problem. If you are trying to infer population values from this sample, there is no real validity. But I am sure it will be interesting to some.
Click to expand...

If the objective is to only gather data from a small number of people at RC who choose to participtae, and the data is presented as such and nothing more, then the study is scientifically valid because it is designed to exactly give those data ;).

But if the objective is to determine the exact lifespan of all fishes that has ever lived in captivity, then of course this study will only in a very limited way do that, and hence not be scientifically valid at answering that question.

Here's what I hope will happen, though: Many people from many different forums answers. What will this tell us? First it will tell us the average lifespan of different species held in captivity by above average skilled aquarists (because that is what people who hang out at forums are). This is of value when you decide upon your next purchase because after all, many people want value for money and thus a fish that will probably live long. Next, the distribution of lifespans tells us how difficult it is to keep that particular species for a long time. If ALL recorded fish of that species die before they have been 2 years in the tanks, then this fish will probably die early in your tank, too. If, on the other hand, a few people (like less than 5 %) have kept it for 10+ years, then it may be considered a difficult fish. A fish that MANY people get to keep for 10+ years (like more than 50 %), must be considered both to have a long lifespan in captivity and to be ease to care for.

Again, this all depends on getting a huge sample size, so good people, please participate! :)
 
Again, the results will not have scientific validity but they may prove interesting to some
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I agree, I'm not sure how much actual value it will have but may help someone or prove interesting.

If you've been around the hobby for 5- 10 plus years you know what species are long lived & which to avoid. One of the biggest variables that won't be shown is the experience of the hobbyist. If you have 20 years in the hobby like I do, fish don't die very often.........maybe every 10 years or so. The biggest killer of fish is the aquarist himself. Mistakes like improper care, maintenance, no QT, ect. are often the killers of fish................they seldom die of old age.

I'd be willing to bet most yellow tangs die the first year, because so many novice aquarists buy them, but in reality this is a fish that should live for 20years under proper care.
 
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Big E said:
If you've been around the hobby for 5- 10 plus years you know what species are long lived & which to avoid. One of the biggest variables that won't be shown is the experience of the hobbyist. If you have 20 years in the hobby like I do, fish don't die very often.........maybe every 10 years or so. The biggest killer of fish is the aquarist himself. Mistakes like improper care, maintenance, no QT, ect. are often the killers of fish................they seldom die of old age.

I'd be willing to bet most yellow tangs die the first year, because so many novice aquarists buy them, but in reality this is a fish that should live for 20years under proper care.
Click to expand...

The idea here is to get some actual empiric evidence that confirms what experienced hobbyists believe. The lifespans in the survey for yellow tangs may be that 80 % of participants reports that it dies before 3 years, while 10 % reports that it lived for more than 10 years. This is highly interesting data. It tells us that this fish has the potential to live for a long time, but that in most cases it doesn't (probably because it is a popular fish that many people are not able to care properly for).

Another example is Banggai cardinals. The lifespan of this fish in captivity is only a few years. And this will be confirmed by the survey. What does this tell us? Well, it tells us that if you want to have a fish for a long time you'd better go with another fish.

Some fish might even end up with a distribution of "lifespans" skewed towards many years, e.g. clownfish, and this tells us that these fish are hardy and may live very long.

Again, many of you experienced reefers might have told us this already, based on your experience and knowledge, but it is much better with actual empirical evidence. And besides, what about the lesser known fish? If enough people participates we might actually get some data on them as well.
 
Hi,

I've post a note on my blog, and on my local French forum, about your survey. each note is asking participants to collaborate in spreading the link to other forums, to gather the most people possible.

As you said, data would only have an interesting profile only if a lot of people answer.

But there's still some problems in the figure collection, as for example, I replied that I had a banggai cardinalfish who lived less than 1 year: actually, my first couple was not a couple, but same sex specimens, so one killed the other one within 2 weeks after getting in the tank... but the other one still here alive since 5 years now, and she's even a breeding pair with the mate I added after the death of the first one, and I raise young cardinalfish, giving the aroundme to other reefer... so one fish died, but the other one is 5 years old, and she's the source of 10th of new cardinalfish I've bred...
so statistics can lie, because all that appears in my answer of the survey is that I had one cardinalfish that live less than one year, period...

it's hard to get true figures with living material...

cheers,
sabine
 
While I agree there may be some interest in the results, I stick with the statement in my original post. Even if you get a huge number of RC participants (you almost certainly will not), as Big E states, aquarist inexperience or in some cases, malfeasance, makes the concept problematical.
 
kactusficus said:
Hi,

I've post a note on my blog, and on my local French forum, about your survey. each note is asking participants to collaborate in spreading the link to other forums, to gather the most people possible.

As you said, data would only have an interesting profile only if a lot of people answer.

But there's still some problems in the figure collection, as for example, I replied that I had a banggai cardinalfish who lived less than 1 year: actually, my first couple was not a couple, but same sex specimens, so one killed the other one within 2 weeks after getting in the tank... but the other one still here alive since 5 years now, and she's even a breeding pair with the mate I added after the death of the first one, and I raise young cardinalfish, giving the aroundme to other reefer... so one fish died, but the other one is 5 years old, and she's the source of 10th of new cardinalfish I've bred...
so statistics can lie, because all that appears in my answer of the survey is that I had one cardinalfish that live less than one year, period...

it's hard to get true figures with living material...
Click to expand...

Thanks again!!

When it comes to living vs deceased fish, this survey attempts to collect data on deceased fish only and hence that is all the data will ever say anything about. So the statistics don't lie, only people who try to use the data to say something about something the data is unable to.

What this mean practically, is that there will be a huge bias towards fish that has died early (because many of the old fish has not died yet). But since this bias is general (affecting all species in the survey equally) it will still be possible to compare the distribution of "lifespans" towards different species. An example: If we compare clownfish and cardinals again, most clownfish will probably have died after 0-5 years (because, alas, that's the fate of most fish in our tanks), but there will be some hobbyists that have had clowns die from them after more than 5 years. With cardinals, on the other hand, there will be relatively much fewer that has lived passed their 5th year. And hence a conclusion would be that if you want a long-lived fish you should go for the clown rather than the cardinal. Similar conclusions may be drawn for all the other fish, hopefully.

Again, thanks for telling people about the survey :)
 
snorvich said:
While I agree there may be some interest in the results, I stick with the statement in my original post. Even if you get a huge number of RC participants (you almost certainly will not)
Click to expand...

Why the pessimism? Are people not interested in helping out when it only takes a few minutes? Here are a hypothetical example of that data I hope to get out of this survey:

Untitled-2.jpg


I expect a huge bias towards fish that die early, but hopefully -- and it looks promising so far -- hobbyists with 10+ years experience with different species will contribute as well making it possible to do comparative analyses of the distribution of time before death after transfer to a new tank between different fish species (as demonstrated in the graph above).

snorvich said:
as Big E states, aquarist inexperience or in some cases, malfeasance, makes the concept problematical.
Click to expand...

Again, I do not want to investigate only how long they live under optimal conditions, I want to investigate how long they live under real life conditions. So even when a hobbyist is unlucky -- or plain incompetent -- and kills off lots of fish due to bad water quality, some might survive and die later because of "age", and such results are extremely important because they follow from different tolerance to suboptimal water quality, a characteristics that varies a lot between species. What I am trying to say is that I want people to add fish that dies because of accidents, because of malfeasance, because of stupidity and neglect, because it will show up as hardiness in the results. A fish that is simply too sensitive to survive in the hands of anyone excepts the greatest experts will have a huge die-off in the first years, while there will be a few that survives to die as old specimen, and this will be clearly shown in the data -- telling everyone that this fish may live for a long time but is very tricky.
 
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