Mine have grown that fast too.. it's amazing.
bitbot asked me a lot of questions about my previous post.. took me a while to answer all that, so here it is.
Granted, an odd thing of 'Mr Mills' to say.
But what does your source mean by 'potential'?
Hi bitbot. I don't know the author so I'll not speculate what his use of the word means to him. That would be pointless. But I will explain what I meant by "potential" and tell you why I think it's a valid expectation to have. (See below for that part.) As for the article, you'd asked me for a source where someone (other than me) suggested that comets have the potential to grow 18 inches or more in length, given the right conditions - so I gave you one which I felt had been well researched by someone who also seemed reasonably credible. This was why I had saved that article in the first place. But this write-up isn't the only place where people talk about comets (and/or commons, wakins, shubunkins) having the potential to grow that long. So, I'll give you more examples of this (with all the links so you can locate the sources).
BTW, the first one came from Flaringshutter's post in "Full grown goldfish size.." That's a reference thread in our Temperate/Cold Water Forum. (Her statement is found in the second post of that thread.) Also.. some of these references came from discussions or exchanges which also discuss tank size requirements or a comet's lifespan. I've included those, as well, because it's relevant to the question. Obviously, a fish's potential length is a factor determined in large part by the care given/space provided and how long the fish lives. (Also note where people are using the words "average" or "potential" -- I'll get to the distinction between those terms too, later in this post.)
<< From Flaringshutter >> "Common, American/Japanese shubunkin and comet goldfish will all reach an
adult size of between 14 and 18 inches, depending on aquarium conditions and diet. Commons will be fatter than comets and shubunkins. Bristol (English) shubunkins grow to 12-14 inches."
http://www.aquariacentral.com/forums/showthread.php?t=133948
"Slender in body shape and have long single tail fin. They are very hardy fish and will grow on
an average of 12-14" long."
http://www.kokosgoldfish.com/ftypes.html
"Size and Life Span: Pond Comets will grow to 12" and bigger. They have a live span of over 20 years, and
some have lived to be over 70 years old."
http://www.****************/catalog_pages/goldfish_and_koi/comet_pond.htm
"Actually, comet goldfishes grow very long tails -- thus the comet name. No one pays too much attention to this nicety anymore. Tails seem to grow longer on indoor specimens --
often as long as their bodies."
"Those little two-inch feeder comets could live for up to 10 years and attain a foot in length
(plus fins). When you see huge goldfishes cruising the local golf course, you know where they came from. They outgrew someone’s fish bowl or aquarium. They rarely attain their full size potential when kept in tanks."
http://aqualandpetsplus.com/Live Food, Goldfish.htm
<< Note: I'll add this to say.... the reason comets rarely attain their size potential when kept in tanks is because people usually keep them in aquariums that are too small, they feed them an improper diet, and/or they overcrowd them with too many other fish. >>
"The common goldfish - The one you have seen at the pet shop, 50 crammed into a 5 gallon tank. They are a slender fish with a short sleek tail fin. They are extreamly hardy and
have the potential of reaching 24"/61cm in size. Average life span of 30 years but one has lived for 42 years."
"The commet goldfish - slender body shape with a singel tail fin, much longer tail that of the common goldfish. Thay are very hardy fish,
that can reach 22"/56cm in length. Average lifespan of 20 years."
http://www.petclubuk.com/fot/fish/types-of-goldfish/95
"The environment the Common Goldfish is kept in is a determining factor on whether your pet
grows to its full potential size or is somewhat smaller. If kept in a spacious pond they can reach over 12 inches (30+ cm), with some hobbyist reporting their Common Goldfish
reaching up to a whopping 18" (45+ cm)!"
http://animal-world.com/encyclo/fresh/goldfish/CommonGoldfish.php
Wakin Goldfish has a more fantail shaped caudal fin, but the fin is not very long. This goldfish can grow very large, and
the longest measured Wakin Goldfisih was 18 inches long.
http://www.aquaticcommunity.com/goldfish/wakin.php
If there is not a single goldfish anywhere in the world larger than about 18 inches, what does he mean when he says that a goldfish has the potential to reach 61cm?
This makes sense if you note the difference between the actual size of a 20 year old comet (today) compared to the potential size a juvenile comet that's 2 inches long will have over the next 20 years. Let's look at how changing some of the wording makes a real big difference. For this, I'm going to use my own numbers now for illustrative purpose.
Average length - I would say that most comets average somewhere between 12-14 inches long. This would be the usual size range for a standard fish at a mature/adult age, given adequate food and fairly decent conditions. This is an average now.. a median point between the shortest and longest actual fish lengths for most comets that people might normally find in fish tanks and in ponds. Those that are given better food and better living conditions will reach the longer lengths and those that are given less ideal conditions... won't. (Genetics and overall health/longetivity would obviously also factor into this.)
Actual length - Apparently, the longest documented goldfish seems to be 18.7 inches. Okay, but we've also seen examples (above) where comets have already grown to 18 inches or so. That doesn't seem to be unusual for comets. While comets at that length don't break the existing world record, they still come in real close to the same size.
Potential length - I expect the potential length for a two-inch comet that someone buys today will exceed the average length (of 12-14 inches) and possibly even the current world record length (of 18.7 inches) if that fish is given the right conditions over the course of its entire lifespan; i.e., as in nutritious food, good care, clean water, appropriate tank mates, proper environment, and so on.
Here's why. That "world's longest fish" on record right now was hatched some 15-20 years ago. Look back to what we collectively believed "good" conditions were for a developing fish back then vs. what we've learned about their care/requirements over the last two decades. In the past, most people believed 10 gallons of water per fish was enough for comets. Now, we typically recommend 20 gallons or more. Over the years, we've found out a few things about comets and about better methods of fishkeeping in general. We know that they generally get bigger in pond environments because they are given more room. And that fish that are kept indoors in aquariums typically develop longer fins (which applies to the tail's length). So it makes sense to give comets the water volume they need to fully grow and develop when we keep them in an aquarium. As a result, we'll get full grown comets with longer tail development. Breeders keep improving the genetic bloodlines of the high quality stock they use in their breeding programs. While the "premium" fish they produce usually go to other breeders, collectors, or exhibitors... the many thousands that weren't culled (sick/deformed/substandard) are the ones we find in regular pet stores or feeder tanks. While these may not be "show quality" fish (although many still are)... they also benefit physically and genetically from the selective breeding programs in place where they were hatched. Many breeders are cultivating fish specifically to further develop certain physical characteristics, such as the shape or length of the tail fin. Newer, more beneficial, and highly nutritious food products have been formulated over the years that are commonly available to fishkeepers everywhere now through commercial sources. These products were't available many years ago because they didn't exist then. Given so many advances and improvements that exist today within the hobby PLUS the access we have to better education, knowledge, expertise in fishkeeping overall... these factors are all going to give us healthier, longer living, more hardy, larger, and.. yes... longer fish than it did so many years ago.
There are many dedicated and resourceful breeders in the world; don't you think one of them, somehwere, would have a goldfish that had reached its 'potential'?
Well, that gets back to a matter of time again, bitbot. It will be another 15-20 years or so before their current generation of hatchlings/juveniles will reach an ultimate mature length (today's potential) at the end of those fishes' full lifespan. What I think is... the potential today is higher now than it used to be many years ago, for many of the reasons I listed above. I also wouldn't imagine that breeders would have all those old, mature breeding fish still at the latter years of their lives. They get rid of older fish that aren't breeding anymore if for no other reason than to make room for new breeding stock. Breeders don't hold on to all the same individual fish forever... certainly not beyond their "prime" breeding years. I also doubt that an intensively (over)bred fish kept in that environment for so many years would ever reach its full lifespan anyway. Constant breeding over a long time would likely shorten the fish's longevity. So, no... I would not expect breeder stock fish to ever reach their true potential, neither in length nor longevity. But their offspring might, depending on where they end up and the conditions in which they are kept.
I couldn't find the sources.
And I'm still skeptical about these 'potential' sizes, but the article was interesting.
I think it's an interesting question too. And yes, I can give several reasons or cite other sources to explain .. but people are going to come to their own conclusions based on their own judgements and experiences.
My underlying point is that it is extraordinary for a goldfish to reach 45cm (18 inches) or more, and the fact that it doesn't is not necessarily due to inadequate care; and I think it is of limited relevance to the question of stocking levels.
On this, it seems we disagree completely. I believe adequate care and stocking levels are both huge factors when comes to the fish's health, well being, growth, and longevity. All of which combined are what determines whether a particular fish will reach it's potential length or not. Even with good genetics and high quality foods... a stunted, unhealthy, short-lived, or overcrowded fish isn't going to fare as well over the long term.
Talking about stocking levels, again... Here's a question/answer site where tank requirements for a comet were discussed. It's not even a fish site, but the advice given was pretty good. The great dane puppy reference made me laugh, but it also illustrates the point about tank size/stocking levels.
Question:
"I have a comet gold fish can i put two in the same tank i thank its preety big tank for both of them? P.S its very little Fish. i really think its a 1 gallon."
Answers:
"kid, i can't stress this enough. goldfish WILL NOT stay small. especially not comets. the only way they will stay small is if you kill them before they are adults (which is tragically common)."
"trying to keep a goldfish in a single gallon is like trying to keep a great dane puppy in a purse 24/7 and saying "it's okay if he dies before he's an adult i don't want a big dog anyway".
"and contrary to poplar belief goldfish are not stupid. studies show their memories last many years. so please don't justify it saying "it's just a fish". care for it properly or find it a new home."
"your comet goldfish has the potential to grow over 12"-14" long with proper care, they're pond fish really, NOT tank fish. and 1 gallon is no way large enough for a single comet, it needs a minimum of 10-15 gallons until it's about 4"-5", then an upgrade to either a 40-60 gallon or a nice big pond in the spring. really with goldfish you want to buy a home that can accomodate their full adult size for their full life span (which should be over 20 years!). and over-filtered at that as goldfish are exceptionally messy fish. there is no such thing as a "small" or "dwarf" goldfish. only babies, stunted, sickly and dead."
"I have to agree with basically everyone else on here. It's a common misconception that small goldfish can be kept in small bowls, but nothing could be further from the truth. Goldfish have the potential to get very large and live a very long time. The minimum, bare minimum, I've heard for fancy breeds is a 20 gallon tank for one fish. However, comets can get very, very large. I would suggest about 40 gallons for an adult comet. Goldfish are notorious for the amount of waste, particularly ammonia levels, they create. This means that small containers quickly become toxic for them. They need more water and a healthy amount of filtration and oxygenation. When goldfish are placed in smaller containers, the body produces chemicals that stunt its growth. Though it appears the fish is simply staying small, it's actually damaging the fish's health and shortening its lifespan."
http://answers.yahoo.com/question/index?qid=20080205114329AAAdqG7
