Goldfish Really Coldwater Fish? Not Really!

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ArauraDiscus

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From what I have read, goldfish are in fact not a coldwater fish. Some people worry that their tanks can get too hot, but many fail to realize that goldfish and carp/koi originate from north america and china, both temperate zones. Water temperatures range from 32-82 degrees F. While yes goldfish can tolerate these near freezing temperatures, does that really mean they prefer these stressful and cold temperatures? No, they prefer tropical temperatures as well. They seem to like it around the mid 70's in F.

In fact when defining a coldwater fish, should we not say that a true coldwater fish is not happy above a cooler temperature. The common temperature thrown around for coldwater fish seems to be 68. And fish like sterlet and sturgeon become weak and sickly above this temperature. They are true coldwater fish because they enjoy these cooler temperatures and depend on these temperatures.

So since goldfish don't need a heater for their tank, they can withstand a broad range of temperatures which just goes to show that they are a temperate water fish, not a coldwater fish.

Thoughts?
 
I agree with you, personally I think that goldfish are classified as "cold-water fish" because they're commonly seen in ponds and in man-made lakes, people assosiate the "cold" water in these areas to mean that these fish are true cold water fish.
 
Goldfish are extremely hardy and can adapt to an extremely wide range of temperatures. My dad has had a goldfish pond in the back yard for almost 50 years. The pond is about 12' in diameter and 18" to 20" deep. We live in North Carolina and I can remember seeing 4" to 6" of ice on the top in the winter and temperatures in the 100s in the summer. I can emember that for probably 20 t 30 of those years, there was no pmp or aeration on the pond. Just what surface disturbance that mother natue provides with the wind and rain. Through all this, he has rarely lost a fish except to age (and a huge owl and blue heron that decided the pond was a great place to get dinner). While keeping them in a tropical tank may not be the perfect scenerio, they can adjust just as we say that a tetra or angelfish will adjust to someone's tap water with a pH of 7.6. It's not optimal but the fish will be fine.
 
Yes, but equally people interpret 'cold water' wrongly. Ponds exempted, cold water tanks are actually room temperature.

For scientific calculations, room temperature is taken to be roughly 20 to 23 degrees Celsius with an average of 21 °C, about 72.5 degrees Fahrenheit (°F)

'Cold water' (the term that is used by aquarists, as various places have different interpretations. If you've seen the article on fish imports in PFK, the definition used by importers is that a coldwater fish is one that can contract certain diseases) is merely a way of quickyl identifying the fish that are fine at room temperature and those that generally prefer it warmer. Definitions get blurred occasionally, but it works pretty well as a guideline.
 
Cold water is probably an inappropriate classification for them as they are found naturally in all kinds of climates, and can tolerate a wide range of temperatures.
 
when i first started working at my shop, the goldfish were all kept in the tropical section. each morning i would check the tank for 'sleepers' and would find 1 or two each day. we constantly fought battles against blackmoors dropping of from slimey skin and other random issues. originally it was argued that it was because the system was new but indeed it had been running for 9 months.

when i bought the store, i redid the fish section and put the goldfish in a massive cold water display tank. i keep the air conditioning running non stop in the shop to avoid the build up of humidity from all the tanks. too much humidity in the past started blowing starters in tank lights, creating mould on my roof and makiing the zippers on all the dog jumpers go rusty. so the shop is constantly at a temp of around 19-20. the water in the GF tank is about the same if not a little lower at times.

since putting them into the cold water tank, i have not lost one. had no issues with disease, lethargy or anything else.

this is my untrained view on goldfish: while they come from temperate areas, it seems to me that as much as they can survive in warmer temps, it seems they are healthier in the cold.

two more examples come from two different customers of mine

1) a lady came into the shop the buy some pacific blue eyes for her pond. while she was there she asked me for another couple of goldfish because her two died. she was complaining that she could keep any fish alive except for goldfish. this lady was coming in every week buying goldfish. i had never served her before as the girl who was working there always got her. she bought two goldfish everytime and gave a sizeable tip as well (tipping is rarely heard of in australia, so someone who tips is like gold :)) anyhoo i digress. i asked what size her tank was etc etc the goldfish were kept in a tank heated to 25.5.

i suggested to her that she try removing the heater or even for her to put the goldfish in her pond. she opted for the pond and bought a hefty load of fish for her tropical tank. i didnt see her for 7 weeks until last week. she has reported zero deaths and everyone is doing well. and we are in the middle of winter here.

2) old man. keeps 3 6 foot tanks full of goldfish (not overfull though). all heated tanks. he's old and set in his ways and apparently prefers to come in every month and buy 30 goldfish for $150 ($5 each) rather than take the heaters out. he bought some of them in one day so i could have a look and tell him what disease they had. he also bought water samples. water was perfect as i had suspected. the fish are everything as his wife passed away last year. the fish he bought in looked in ok health. no visible signs of anything on the outside. obviously i cant speak for the inside. his daughter was with him this day so i asked her to convince her father to try taking the heaters out.

5 weeks later he comes back in with a bunch of flowers for me :) he had decided to try this coldwater thing and low and behold, he has lost no fish this month :) i will miss his custom though :)

i know this isnt conclusive evidence but my experiences with them are leading me to believe that they do thrive better on colder waters.
 
since putting them into the cold water tank, i have not lost one. had no issues with disease, lethargy or anything else.

this is my untrained view on goldfish: while they come from temperate areas, it seems to me that as much as they can survive in warmer temps, it seems they are healthier in the cold.


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I think this is a direct relation to the diseases prefered temperatures, and not the fishes. Many disease are stunted or inactive below 70 degrees farenheit. Many are extremely slow to multiply if they do at all and the fish fight off or withstand their small numbers. This is why your fish are appearing healthier in colder water. But I think that the fish itself likes the mid 70's while the bacteria and parasites like those temperatures even more.
 
I have had an outdoor goldfish pond for about 7 years. My pond has gone from frozen 9 inches down to the low 90's. My fish seem the happiest with the water around 70-75. They are the most active and seem the most lively at those temperatures. Above 82 or so they get lethargic except at feeding time. Below 60 and they are very lethargic and have no desire to eat. I do not feed them from around October through march-april. These are just feeder fish that I've had almost 7 years. I started with a dozen and 5 died within 2 days. One died around 3 years ago and one was eaten by a heron. Otherwise the 5 remaining are all at least 8" and very healthy.
 
Sounds like goldfish do well in cold water, but one thing I have found (a bit off the topic) is that I could never keep one alive in a bowl without a filter. As soon as I switched to a tank with a filter, they lasted for years.
 
Sounds like goldfish do well in cold water, but one thing I have found (a bit off the topic) is that I could never keep one alive in a bowl without a filter. As soon as I switched to a tank with a filter, they lasted for years.

100% daliy water changes sort that, i know one fish with no filter that is over 7 inches long and shines like a diamond in the sun.

true goldies can survive in warmer waters. but the will suffer from the lack of oxygen, be far more prone to bacterial and other infections. many things can survive well out of their proper range, however surviving and thriving are two different things.
 
My fish seem the happiest with the water around 70-75. They are the most active and seem the most lively at those temperatures. Above 82 or so they get lethargic except at feeding time. Below 60 and they are very lethargic and have no desire to eat. I do not feed them from around October through march-april.
The reason the fish are less active in colder temperatures is because they are ectothermic. Their metabolism is dictated by the ambient temperature. As the temperature cools down they slow down. The reason for not feeding temperate fish in winter is beacuse their metabolsim is slowed down to the point that they do not need any further food for energy.

Goldfish are temperate fish, meaning they inhabit waters with an annual range from around 6 degrees up to around 20 degrees. I would expect a shorter life if kept permanently at higher temperatures as the metabolism will be faster on an annual average than in the wild.
 
Just commenting to say, fishlette, your story with the old man and the flowers is just so sweet. It's so awesome when you get lovely customers like that. I work at a major supermarket chain as a checkout wench (think of the main two, its one of those) and sweet customers like that are few and far between. For every nice person who leaves a lasting impression you get at least 10-20 nasty ones. There's this one old man who comes in everyday, and last year on HIS birthday he brought all of us chocolates. And there's another lady who always brings an ice cream tub full of homemade popcorn and offers it to everyone as she goes around, haha.

More on topic, I feel so, so bad now about how I used to treat my goldfish before I knew anything about fishkeeping - I learnt when I got my big tank and decided to take on tropicals. I used to keep them in an unfiltered bowl, and it would sometimes go weeks and weeks without being changed - it's be cleaned when it LOOKED dirty. They were small (obviously I stunted them) but amazingly some of them lived a year or two (but I killed a lot too, and obviously goldfish can live a lot longer than that :() I guess the important thing is that I know better now, and I've been able to tell people who are making the same mistakes I used to.
 

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