3-Pound Goldfish Found—How’d It Get So Big?

As an avid fisher for 20 years, Mike Martin has his fair share of stories. Many fishers can tell tales of the one that got away, but Martin’s latest yarn is all about the one he reeled in earlier this month on Lake St. Clair (map), just north of Detroit, Michigan.

“Basically, I was doing what I always do, trying to catch perch, and I thought I had a big perch on. Um, definitely not a perch,” Martin told WDIV News, the NBC affiliate in Detroit. (Watch a video of the giant goldfish on

A 15-inch goldfish named Bruce is lifted from the water at a fish farm in Dongguan, China, in 2002. Photograph by Bobby Yip/Reuters

Indeed not. On his hook was a 15-inch-long (38-centimeter-long) goldfish that tipped the scales at 3 pounds (1.4 kilograms). Compare that to an average aquarium goldfish that generally measures just a few inches—their breeds come in a wide variety of sizes—and it doesn’t take long to figure out that this whopper of a fish is going to need a bigger bowl. (See a picture of a see-through goldfish.)

That begs the question: What exactly is a goldfish, and how can they get so freakishly big?

Goldfish: Carp in Pretty Clothing

Goldfish are actually a type of domesticated carp. Almost 2,000 years ago, the ancient Chinese began to domesticate Prussian carp, Carassius gibelio, for food and as ornamental fish.

Over time, mutations creating orange, red, and yellow colors began to emerge in the dull-colored Prussian carp, creating the coloring we now associate with goldfish. The fish was transported to Europe in the 1600s and to the United States in the 1850s.

Although not naturally found in the wild, goldfish have occasionally been found in ponds, lakes, and streams. Most researchers believe that these goldfish were either dumped there or somehow escaped from the “porcelain express” after being flushed down the toilet.

Many of the unusually massive goldfish—like the one Martin caught—have been found in these outdoor settings, but goldfish experts say it’s a myth that a large tank will yield large goldfish. (See pictures of the world’s monster fish.)

Big Fish in a Small Pond

To grow a big goldfish in a small pond, breeders focus on two main factors: food and temperature, according to Tropical Fish Data, a database on tropical fish. A high-protein diet is generally thought to increase the body weight of a goldfish, as is being fed more food, more often.

Warm water also increases a goldfish’s size. Goldfish kept in outdoor ornamental ponds generally grow quickly in summer and little, if at all, over winter. Keeping goldfish in a heated aquarium allows them to maintain their summer growth spurt year-round.

The longest known goldfish, according to Guinness Book of World Records, measures 18.7 inches (47.4 centimeters) from nose to fin and belongs to Joris Gijsbers of the Netherlands. Guinness did not have any official recordings of the fish’s weight, so it’s unclear if the Dutch goldfish beat the new Lake St. Clair goldfish in bulk as well as length. (Also see Biggest Great White Shark Caught, Released.”)

Martin hasn’t purchased a swimming-pool-size fish tank for the goldfish he caught, nor is he hosting a neighborhood fish fry. Instead, he’s currently keeping the specimen in his freezer—he ultimately intends to mount it on his wall.

Carrie Arnold is a freelance science writer living in Virginia. When she’s not writing about cool critters, she’s spending time outside, drinking coffee, or knitting.


  1. Bill oFell
    Mt Pleasant michigan
    August 6, 3:29 pm

    Wow. We have at least a 3 to 5 pound goldfish swimming in the retention pond in front of our residence hall. I feed it bread and corn all the time!!!

  2. Something
    July 22, 9:07 am

    I do not understand why people are angry that the fish was killed. Firstly the fish did not belong where it was living. Secondly if it were any other fish you probably wouldn’t care. Fish are killed all the time, the only time you should truly worry about someone killing a fish is if it is endangered.

  3. James Dickson
    February 15, 2016, 1:58 am

    Very informative blog..I love to read the goldfish swallowing blogs and after that, I result up to website where similar kind of videos and information

  4. Lilly
    November 29, 2015, 11:08 am

    How did it get so big? Because it’s a goldfish! Goldfish quite simply get big. That’s like asking how did an elephant get so big. And I find it hard to trust this article (from national geographic, no less!) after it said goldfish only “get a few inches” and “need a bowl.” Goldfish on average get 8-14 inches long and need 20 gallons per fish. A bowl is unnacceptable

  5. Thatguy
    Chattanooga, TN
    August 30, 2015, 3:43 pm

    He should have put it in a personal pond or tank. I have three goldfish in a 55 tank that WILL NOT STOP GROWING and they dont need to be stuck in my freezer.

  6. Chelsea McCluer
    West Michigan
    January 30, 2014, 4:16 pm

    I love how people think the fish in the picture is the one that was caught. The fish in the photo is Bruce, the World’s largest Oranda. Mike didn’t catch that.

  7. Nathan
    December 14, 2013, 12:09 pm

    Yeah why not let the poor creature live. The worst it could do is find another goldfish, breed, become the parents of millions of goldfish that make their way through a ton of midwestern streams and lakes killing native fishes as it steals food and eats several smaller fish and destroying plantlife all along the way. But sure let it live just the same way as we should let asian carp live. Think before you speak people

  8. Pam
    United States
    November 3, 2013, 9:16 pm

    He killed that gorgeous creature so he can mount it on his wall? That’s disgusting. I’m appalled at the lack of compassion people like this guy have for sentient creatures. He should not be celebrated, he should be condemned.

  9. michael allen
    October 10, 2013, 10:00 am

    my pet goldfish was 5 pounds before it died.
    and this is shocking news?
    i thought that 3 pounds was average for a full grown goldfish

  10. Josh
    September 1, 2013, 8:00 pm

    Donate that fish at Their model won’t eat that kind af big!

  11. Davie
    March 29, 2013, 12:00 pm

    I am agree with @Marcos Uchoa,It is right that what did he say!

    we are exporting the best quality goldfish and good price in shanghai,china

  12. Suzanne Spittal
    March 23, 2013, 4:55 am

    I sincerely hope this fish was put back in the water immediately and not allowed to die just for the sake of taking some pictures.

  13. Joe Brown
    February 27, 2013, 9:58 am

    Goldfish in the mill dams at coats threadmills Paisley were easily 3lbs and more.

  14. ryan
    February 12, 2013, 2:12 pm

    HA! I’ve been keeping fish for 15 years and I always told people goldfish get huge, this is just more proof!

  15. Markos
    South africa
    February 7, 2013, 2:34 am

    Wow amazing

  16. Candace
    January 22, 2013, 11:12 pm

    Nice catch! To those people who are upset that he killed the fish clearly never fished before or don’t understand the sport. You don’t throw invasives back into the water. It’s already a concerning problem in the Great Lakes as well as the Mississippi River with Asian carp. Goldfish are carp as well and are non native to the region. Contact your local DNR and they will give you a huge list of invasive fish that they are trying to destroy.

  17. sydney
    January 22, 2013, 4:31 pm

    i used to live in michigan

  18. rwilsonswife
    January 22, 2013, 1:22 pm

    Clearly the people that have commented on this catch are not fishermen. 9 out of 10 times the fish will swallow a hook and will die. So why not preserve it as a trophy on your wall. Beats eating a Karp not to mention, what are the chances of one catching another 3 pound gold fish in ones life time.

  19. Suzanne Lapensee
    Ontario, Canada
    January 22, 2013, 1:02 pm

    @Mike Martin – you should be ashamed for killing such a beautiful fish. If you aren’t going to eat it, then you’re wasting it and selfishly decided to take its life for your own self glory.

  20. Suzanne Lapensee
    Ontario, Canada
    January 22, 2013, 1:00 pm

    I completely agree with @Paige Potter. I found this to be a fascinating story, but was disgusted at the end when it mentioned that this man killed this beautiful fish. What for? He isn’t planning on eating it – but yet it’s ok to keep it as a trophy? People make me sick. What a waste of a beautiful, strong fish who clearly earned his right for survival and his right to live out the rest of his life without human interference.

  21. lyndon watkins
    New York
    January 22, 2013, 10:39 am

    you guys are idiots. the fish in the picture is not the fish he caught. if you would just read whats underneath the picture. and also if you click on th elink to the video you can see the actual fish.

  22. Lee
    New York City, NY
    January 21, 2013, 7:28 pm

    gluttonous goldfish….

  23. Bill Cody
    Syracuse NY
    January 21, 2013, 1:21 pm

    That gold fish is called an Oranda. They are slow, docile, aquarium fish and big ones are expensive. Killing it was not a smart move.

  24. samsi77
    Bloomfield Hills, MI
    January 21, 2013, 10:47 am

    creepy yet fascinating to view the actual size of the goldfish!

  25. Alison
    January 21, 2013, 8:28 am

    I also wish he’d thrown it back into the water!!

  26. Bob
    January 21, 2013, 8:02 am

    I have them about that big in my pond . It’s about 2.5 ft deep and kidney shaped 10ft x 5ft . I used to have koi but the freakin blue heron used it as a buffet. So off to pets mart for gold fish a 10 cents a piece. Last count there were 26 fish in there. I only bought a dozen. They looked like fishsicles yesterday but i did not hear any complaints. lol

  27. Paige Potter
    South Africa
    January 20, 2013, 1:51 pm

    I think this was such an interesting article but I am extremely disappointed this person didn’t throw such a beautiful specimen back. It had lived a successful life and was obviously a healthy and strong fish and it deserved to live out it’s life rather than be displayed on some one’s wall.

  28. Rei
    January 20, 2013, 12:07 pm

    People are either compaining that he didn’t release the fish, or about how dangerous this fish is to the ecosystem.

    Do any of you even know what you’re talking about?
    First, does this fish look like it’s fast enough to get away from any predators? Does it look like it’s dull enough to HIDE from any predators? Some goldfish are so deformed through breeding that they can no longer breed naturally. So don’t worry about overpopulation. Karp on the other hand…

    Second, fisherman fish for prizes. There are laws that keep them from taking certain fish with them, but whatever else they catch, they can do what ever the hell they want with it. If he released it, I think it’s about good as dead.

    Personally, I would prefer to have kept it live, maybe sell to a local fish store if I can’t keep it myself, but not everyone has fish KEEPING skills/desire to keep fish.

  29. Jennifer
    January 20, 2013, 11:38 am

    What a dick for killing that beautiful fish…instead of mounting it on the wall donate it to an aquarium..he survived against the odds to grow that large and you made him into an suck !!!

    January 20, 2013, 10:57 am

    It is not that uncommon for goldfish to grow into that size in China. In fact I’ve seen larger. But don’t worry. It won’t destroy your ecosystem as goldfish in the wild is not much more then a dead fish.

  31. Disher
    January 20, 2013, 10:28 am

    People, you don’t want a fish like this swimming around where it doesn’t belong. Think about this fish out competing naturally occurring species of fish. It would throw off the ecological balance of the lake. Hopefully this goldfish didn’t breed in this lake because it would be nearly impossible to eradicate them at that point.

  32. Dennis Lohfink
    January 20, 2013, 10:23 am

    If that goldfish was down here in Florida our Largemouth Bass would have done ate that goldfish, cant be that bright swimming around when the predators here can swallow you whole

  33. Lemon
    January 20, 2013, 10:09 am

    the fish died?! sad. :c

  34. Damon Earl Warren
    January 20, 2013, 9:46 am

    Howard Sprague on Andy Griffith caught Ole Sam, a rare silver carp and set him free! An episode this angler apparently never saw…

  35. Jenny
    January 20, 2013, 8:59 am

    What a fascinating story! Now I can’t get the image out of my head of a very large fish popping out, fishlips first, from a teeny tiny fishbowl.

    Regarding the comments criticizing Mr. Martin for not releasing the fish: could ornamental carp become invasive in the upper midwest? Although a thing of beauty, it seems rather good that this non-native fish hasn’t been left to lay its eggs all over Lake Clair.

  36. Clarissah
    January 20, 2013, 8:57 am

    I too wish to express my sadness that this fish was not released. The fact that it’s such an oddity, maybe you could have left it to live out it’s life rather than be mounted in the wall.
    Disappointing and selfish IMO

  37. Smithers
    January 20, 2013, 8:22 am

    And he didn’t release the poor thing? What a douchebag.

  38. Common Sense
    January 20, 2013, 8:20 am

    Why didn’t he throw it back?? Because it is an evasive species. He did the right thing getting it out of the system

  39. Marcos Uchoa
    Alagoas, Brazil
    January 20, 2013, 7:30 am

    As a goldfishes breeder and grower for at least 30 years all i must say to you is that all of us think that keeping this kind of fish in artificial aquarium or ponds is the same as if it is kept in natural ponds with large bodies of well oxigenated water and completely balanced diets, wich includes all the the microelements and vitamins reached in algae, mud and insect larvs. It is definetly not. We cant humanize its nature giving them our habits, like breafast, lunch or dinner, mainly with artificial foods, wrong luminosity and stress when kept inside home. They have no stomach and dont stop eating. If you dont know, they dont sleep, too. If you give them a 20 square meter ideal mud pond for fish you will meet the same size of this one above, how it uses to happen here in Northeast of Brazil.

  40. Marie Yu
    January 20, 2013, 6:37 am

    Thank you for sharing!this is great info!

  41. Dee Kat
    January 20, 2013, 5:50 am

    Very sad that he did not release it back.

  42. Vanesa
    Buenos Aires
    January 20, 2013, 5:15 am

    My husband’s cousin had bought 2 carassius fish. One of them died really fast and after a few years, for their sourprise, the remaining one would not stop growing. It got so big as the one in the picture. It was impossible to clean the glass cabinet because it was heavy and they couln’t get it out….It died 2 years ago and it was almost as big as the place he was living. The one who sell them told that they were regular carassius…..We keep pictures of the poor enormous fish.

  43. Antonio
    January 20, 2013, 4:39 am

    Cause it’s normal for a Carassius spp. to reach this size. nothing special.
    It’s only that in an acquarium or in a home pond people don’t provide suitable condition for them.

  44. nora escandelor
    January 20, 2013, 4:21 am

    i wish he did not put that fish in freezer., instead let it swim in pond so others can also enjoy seeing it

  45. Johanna
    January 20, 2013, 4:02 am

    I was hoping he would have thrown the fish back into the lake.

  46. Pete Braun
    Troy, MI
    January 20, 2013, 4:01 am

    This was mentioned on the local news in my area. I couldn’t believe how big that fish was!

  47. Adam
    Columbia Mo
    January 19, 2013, 1:18 pm

    Why didn’t you let the Gold Fish Live? Once you knew it was not the fist you wanted you just put it in your freezer? I don’t understand now your just going to throw it in the garbage.

  48. mjgold
    January 19, 2013, 12:12 pm

    Ho stupid! Why didn’t you throw it back. That was a beautiful fish and you kept it for what purpose? How many people with small ornamental ponds would love to have given that fish a home. This is a shameful thing.

  49. Ima Ryma
    January 19, 2013, 4:20 am

    Two twin goldfish brothers were born
    In a sewer line Mom was in,
    When she’d been flushed one early morn.
    She wished them well as they took fin.
    They made it to a treatment plant,
    And swam to the surface to see
    The human world from their own slant.
    They feared humans instinctively.
    But a worker grabbed them both there.
    Into a tank went each brother.
    Through the glass sides, humans did stare.
    One goldfish said to the other,

    “So it’s a tank – let’s have some fun.”
    “You drive and I will man the gun.”

  50. Tom Huxton
    S.E. Michigan
    January 18, 2013, 11:18 pm

    30 years ago two of us caught a large goldfish while netting suckers near the same area. We were fushing the warm water discharge from the Fermi generating plant. It was not a fancy but an average looking fish, weighing over 5 pounds, with small scales and a very bright red color. I have also observed very large carp colored like koi variieties in red black and white splotches.

  51. Mike Martin
    January 18, 2013, 9:04 pm

    WOW…..Thank You for covering my story.