Saturday, July 24, 2010

World's Longest Goldfish

A recent article on PFK,, about a "Monster Goldfish Hooked By Angler" misled many folks into thinking that this 16" Common Goldfish was a "Monster" when in fact, 16" is a normal size that all properly kept Common Goldfish should reach... with many growing to 18", 20" or more. You can read my short comment and other comments at the bottom of the PFK article and then my much longer reply to the Gold-Fish Yahoo Group below.

This article led to a couple of posts on some of the fish and pond Yahoo Groups which then led to a discussion about the World's Longest Goldfish according to Guinness. Here is one of the emails and then my LONG reply.

-----Original Message-----
On Behalf Of josepha48
Sent: Monday, July 19, 2010 10:44 PM
Subject: [Gold-Fish] Worlds Longest Goldfish

I found this link on the worlds longest goldfish. Over at Guinness Book of World Records. It's the longest. At 18 inches I'm guessing that 12 inches is probably about average.

And now, my reply:

-----Original Message-----
From: Lenny V. aka GoldLenny
Sent: Tuesday, July 20, 2010 11:18 AM
To: ''
Subject: RE: [Gold-Fish] Worlds Longest Goldfish

That Guinness record is for a "pet" goldfish, since Guinness started up that category.

I would venture to say that 99.9% of goldfish kept as pets are stunted to some degree... a large percentage of them are grossly stunted due to being kept in undersized aquariums... or God-forbid, bowls and being underfed as so many stores tell people to only feed them once or twice a day and while that's OK for adults, baby goldfish have a much higher metabolism and should be fed many times a day... just like a human baby. This is why I so strongly recommend at least a 55G, 4' long tank for two fancy goldfish or a tank twice that length for long-bodied goldfish. Even those minimum recommendations will need weekly tank maintenance to keep the pollution levels down.

Try putting some baby common goldfish (leaving at least 100G per goldfish) in a pond (or big aquarium) and properly feed them from birth, meaning 5-6 times a day for the first few months, then cut back to 3-4 times a day for the next few months, then twice a day thereafter. Do proper filter maintenance, bottom cleaning and PWC's and they will be 12" long after a year and 16" by the two year mark.

Many people have these kinds of results even when buying 1" feeder goldfish at a pet store, even though those fish are partially stunted already but they are still young enough to recover if properly taken care of once removed from the overstocked feeder fish tanks., which is THE best scientific resource that hobbyists have for information, says that goldfish grow to a maximum normal length of 59cm (23") in nature.

This 1992-1995 Alabama study (see below link or TinyURL if link breaks) of over 250,000 common goldfish measured their length and weight from 1.5cm (.59") to 40.6 cm (16") to come up with a calculator for determining the weight of a goldfish based on it's length. NOTE - There's likely a reason they studied goldfish up to 16" as that is a normally expected/attainable size. The reason that folks would want to know their fish's body weight is to determine the proper amount of food to feed each day... usually 1% to 3% a day, depending on the water temperatures with less food being fed at lower water temps, down in the 60'sF and then no food fed when the water temps get down into the low 50'sF.

TinyURL -

You can enter your own fish's length (in cm) to find out it's likely weight (in gm).

You can't really use the word "average" when dealing with pet fish length's as the "average" would be severely below what the fish *should* grow to because there is STILL a severe overstocking problem in the hobby due to the bad info given by many pet stores and even many websites still give bad info about goldfish.

Just like with "average" lifespan versus how long a fish *should* live. The "average" lifespan of a pet goldfish is probably a year or two but they should live for 20+ years for long-bodied and 10+ years for fancy goldfish. Here's my "Lifespan" article/list that I've been working on for many years and the REAL *expected* lifespan of pet fish would shock many folks. So many of the most common BIG pet fish (goldfish, common pleco's, oscar cichlids, etc.) should live for a decade AND more, but so many don't make it that long due to being kept in undersized tanks or being overstocked so the stunting causes them many health issues and a much shorter lifespan.


NOTE - Be careful of the 2.5 meter long goldfish *reported* out of Thailand, that is circulating the net.. it's an April Fool's blog. LOL Unfortunately, some legitimate sites are picking it up as a real story.  I expect we'll be countering this story for years to come. Here's Guinness' report about the April Fool's blog.

Lenny Vasbinder


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