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dnalex

Goldfish Life Expectancy & Other Interesting Observations

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Over the years, the discussion frequently returns to the issue of the life expectancy of goldfish, and many of us would quickly rattle off that goldfish can live 10-20 years. Armed with this sort of number, many goldfish keepers, including myself, in turn expect the goldfish in our keeping to live that long, if not longer. Recently, I've become very suspicious of this often quoted number, and set out to try to see what scientists and ichthyologists might have to say about this. Here's what I found. I selected only two sources to present here. One is from the US Geological Survey, and the other is a recent journal article on goldfish in the wild.

Here are the links:

US Geological Survey

http://nas.er.usgs.g...x?SpeciesID=508

This one has tons of references, so that you read more if you are interested.

Recent paper, titled

Population Status of Gold Fish Carassius auratus in Restored East Hammar Marsh, Southern Iraq

http://www.kau.edu.s...57307_27538.pdf

I'm not going to go through all the points of both of these sources, but I will sum up some of the more salient observations, as described.

1. The life expectancy of goldfish was found to be 6-7 years. What this means is that while a certain number of goldfish can live much longer beyond 6-7 years, it's not realistic to expect 10-20 years for all of them. When it comes to certain fancy goldfish types (more round bodied), the average lifespan may be even lower.

2. In the wild, the goldfish diet is composed of 60% brown algae, 20% green algae, 15% zooplankton, and 5% cyanobacteria. This means that MOST of the food that goldfish eat are plant based. You can probably now see why commercial foods can sometimes be so problematic for goldfish.

3. In the wild, the biggest population of goldfish caught are 3-4 years old. My interpretation of this is that the goldfish are in their prime at this age, and go into decline after this.

What does all this mean? Well, first off, it's unrealistic to expect our fish to live 10+ years. It's an amazing bonus when this happens, but the average is 6-7, and less for fancies. Secondly, if you buy goldfish that are already 3-4 years old, that's already half their life expectancy. There's a nice chart of length versus age in the article (for single tails). Finally, most commercial foods are really not in line with what they would eat in the wild.

None of this is really a surprise, but I thought I would share the links with you. :)

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Brains about to explode :wall all the info , very interesting Alex

Edited by Gcourtney

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Really interesting! I look forward to reading the articles (but can't handle any more science today :rofl ) I would think that although 3-4 is a prime age in goldfish in captivity with correct conditions I would expect to see less of a decline only because I feel older goldfish are obviously easier targets in the wild. I feel like 10-20 years is a very long time, if my oldest goldie, Roos, lasts 4 more years in my care I'll be pleased. They just seem to have so many problems sometimes, so that's why I like to raise them young, and they can have the best start possible. When you get older goldies sometimes you don't know any background and it can really cut their lifespan down.

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PSP, you brought up a great point, but I don't think that predation accounts for even the major reason why 6-7 years is the life expextancy. A good chunk of it might be, but I don't think that it would be all.

What might be safe haven from predator in aquaria might be offset by other factors, such as more and increased exposure to pathogens and incompatible foods. So, it might be the life expectancy would be even less in captivity. If it's more, it might not be much more.

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i go for a realistic max of 5 years.. although Rocky is 8+ years now, sometimes, you're just accidently blessed with a fish that breaks all the rules.. :)

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i go for a realistic max of 5 years.. although Rocky is 8+ years now, sometimes, you're just accidently blessed with a fish that breaks all the rules.. :)

I would agree here on the 5 years.

Of course Rocky would break the rules. He's awesome! :rofl

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i go for a realistic max of 5 years.. although Rocky is 8+ years now, sometimes, you're just accidently blessed with a fish that breaks all the rules.. :)

I would agree here on the 5 years.

Of course Rocky would break the rules. He's awesome! :rofl

:stop Rocky is not a HE.. she's a SHE!! :kickbutt

:rofl :rofl life in general shows us that mostly ladies outlive the men :P

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I really wish I knew how old Roos was when I got her in 09 because I've had her for 4ish years now.

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:o

Rockina? Rockette? :rofl :rofl :rofl

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I really wish I knew how old Roos was when I got her in 09 because I've had her for 4ish years now.

do you recall what size/weight she was? and did her eyes look well portioned to her body? ie, not stunted?

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i go for a realistic max of 5 years.. although Rocky is 8+ years now, sometimes, you're just accidently blessed with a fish that breaks all the rules.. :)

I would agree here on the 5 years.

Of course Rocky would break the rules. He's awesome! :rofl

:stop rocky is not a HE.. she's a SHE!! :kickbutt

:rofl :rofl life in general shows us that mostly ladies outlive the men :P

this is true for my family at least

:o

Rockina? Rockette? :rofl :rofl :rofl

really Alex

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I really wish I knew how old Roos was when I got her in 09 because I've had her for 4ish years now.

do you recall what size/weight she was? and did her eyes look well portioned to her body? ie, not stunted?

I have pictures of the day I got her (If I can find them in my photobucket :rofl ) I remember thinking she was huge but looking back on it she's so much larger now. Her fins were a lot shorter. She's really much rounder than even one year ago.

Here we are

NEW002.jpg

The day I got her

DSC08449.jpg

Two weeks ago

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i don't think she would have been more than a year old! that crown was never to be robust eh? :wub:

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i don't think she would have been more than a year old! that crown was never to be robust eh? :wub:

:rofl her wen JUST started growing more the past year or so, after adding progold (and then removing mostly because it makes her gulpy) she started showing lots of white wen growths and ended up getting cheeky wen. She'll never have a huge wen but she put all her energy into her fins, so I don't mind!

Edited by Pearlscaleperfect

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Very interesting!

I am a bit surprised about the fact that 60% of their diet in the wild is brown algae. Now if these guys would please start cleaning their tank walls themselves, that would be great. :D

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Very interesting!

I am a bit surprised about the fact that 60% of their diet in the wild is brown algae. Now if these guys would please start cleaning their tank walls themselves, that would be great. :D

Bamboo eats algae off the back glass..I tell him he needs to eat it off the front and sides where it can be seen!

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I reckon Googs is about 3 years old now (26 months of that in my care) I'm proud of him :wub:

I'm assuming he was 6 months to a year when I bought him because he was only a little smaller then he is now and his eyes were pretty big even then. Also, he got his breeding spots quite soon after I got him. What do you guys think?

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In general, animals in captivity live longer than animals in the wild, and we know that can happen for goldfish. I wish we knew more ways to make that happen.

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*sighs* All your research projects of late seem to be from me providing misinformation on the forum. I'm truly sorry I stated the age of goldfish was an average 10 years. I should know better than to say anything without research :(

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*sighs* All your research projects of late seem to be from me providing misinformation on the forum. I'm truly sorry I stated the age of goldfish was an average 10 years. I should know better than to say anything without research

We were all using that number, Una. :)

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I've had about 5 years of life in my experience. I feel like as they get older you have to be more on point. Tank needs to be cleaner and you need to be more watchful for signs of stress, injury and disease.

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2

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*sighs* All your research projects of late seem to be from me providing misinformation on the forum. I'm truly sorry I stated the age of goldfish was an average 10 years. I should know better than to say anything without research

I've said this many times... This has been the general info provided to us :)

Thanks for doing this research Alex! It's good for us to know so we don't have to feel like failures when our fish don't live to be 10. 3-5 yrs is still a good chunk of time ;)

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I feel like as they get older you have to be more on point. Tank needs to be cleaner and you need to be more watchful for signs of stress, injury and disease.

I agree completely.

It's good for us to know so we don't have to feel like failures when our fish don't live to be 10. 3-5 yrs is still a good chunk of time ;)

Definitely! This was the reason why I wrote this. I think we need to modify our expectations, as a group, of goldfish life expectancy to be around 5-7 years. That doesn't mean that they can't/won't live longer. Obviously they do, and we see examples of this often. When this happens, it's a great bonus, and when it doesn't happen, it's not a failure on your part somehow.

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There has to be a major difference in the life expectancy in the wild and in a protected, maintained pond/tank. Zoo animals live to ages far beyond those of wild animals. While humans living in an undisturbed hunter-gatherer culture have a healthier diet and lifestyle than we do, and may actually be healthier through most of their lives than us, they don't approach our life span.

I suspect predation is huge. Goldfish produce those incredible numbers of eggs because that's how many it takes to replace themselves. When small, they are eaten by aquatic predators. I read a story on another forum from a guy who had his large koi pond almost finished and tossed in a dozen feeder goldies to get an ecosystem going. Things came up and he didn't get back to work on the pond for almost two years only to find the pond was swarming with thousands of little goldfish. He asked for help and was told to put in ONE large mouth bass. The goldfish were gone in a summer. He caught the bass and put in his koi, Frequently people use ONE bluegill in a large pond to avoid overpopulation from fry. These fish aren't big enough to take grown goldfish let alone koi. Avian predators, particularly big ones like herons, egrets, and cranes, like to take the big koi. People who have ponds too large to cover will tell stories of a pond being completely cleaned out by one heron in a week.

The study of the Iraq goldfish was fantastic. They had big numbers for those graphs and got beautiful curves. It's interesting that the fish are still growing at 10 years old, which doesn't support the idea that the older fish are in decline. Most growth curves of feral fish that I've seen are pretty flat after 5 years of age.

I need to read that paper in detail. Thanks for the reference, Alex.

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Shakaho, I agree with your point that away from predation and other dangers of the wild, zoo animals may have a much longer lifespan. Your examples of how important predation can be is duly noted, and that is fascinating how one predator alone can wipe out a rather large prey population.

However, a BIG complicating factor here when it comes to life expectancy, in zoos, and in human homes is the advance of veterinary and medical care. Zoo animals get excellent care. The increased life expectancy in humans is in so many ways attributable to the discovery of antibiotics and so many modern advances in medicine, such as chemotherapeutic agents, advanced surgical procedures, and molecular medicine. Other modern improvements also contribute to increased life expectancy. For example, in humans, life expectancy was around 40 years in the 1800s. By the mid twentieth century, this number had increased to 65, and we are now in the 70s.

None of this is happening with our goldfish. While predators have been removed, I think they are at increased risks of diseases because of more restricted spaces. I agree that perhaps we can achieve some increased life span, but I still think 10+ years as average is not yet realistic.

Perhaps in ponds. :)

Edit: Actually, after some searches, I found some interesting things.

Captive orcas have lower lifespans than wild.

http://www.orcahome.de/lifeexpectancy.htm

Zoo elephants average 17 years, while wild ones average 50+

http://news.nationalgeographic.com/news/2008/12/081211-zoo-elephants_2.html

Captive lions live longer.

http://lions.weebly.com/life-span.html

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