Goldfish prefer warm water?

[Barbvday]

I have some serious concerns about some “advice” some people are giving in a very large fb group called Fish Tank Talk.

there are individuals that are advocating for use of heaters for goldfish based on some research that some guy found over the years. After skimming over it, most research was done on common goldfish and to see if they would prefer to be in warmer over colder water.

I am personally not a seasoned keeper of goldfish, particularly fancy goldfish but I know that there are negative long term effects for goldfish if kept at higher temperatures.

does anyone have any studies or research references to back this one up?

 

thank you.

[gardenman]

The aquaculture folks tend to say that optimal biofiltration takes place above 68 degrees Fahrenheit and below 90 degrees. Fish metabolism also slows down in cooler water. If you want optimal growth then you've got to feed goldfish a lot and feeding goldfish a lot produces lots of waste so you'd want optimal biofiltration. You'd also want the goldfish's metabolism to make optimal use of that food, so you'd want them warm enough to ensure that. I would think a temp of 76-78 would be pretty darn ideal. It's a good range for both biofiltration and their metabolism.

[Andy's Fish Den]

Not scientific by any nature, but I have kept goldfish many times over my fish keeping hobby. One time I was keeping a tank of them, a 55 gallon with a couple fancy ones and a couple comets. My house did not have air conditioning so in the summer, the house would get warm. the goldfish in the summer would become almost lethargic at times, would be at surface gasping for air or just lying on the bottom not doing much activity. Once it would cool down some and thus the house got cool and during winter the goldfish were a lot more active and swimming around. Now, I do know they require more oxygen in the water and that cooler water holds more dissolved oxygen than warmer water, so I had an airstone pumping air bubbles into the tank at all times as well as had a good sized sump filter on the tank.

[Biotope Biologist]

Goldfish prefer 68-72 degrees as optimal temperatures for metabolic rates and growth, as well as higher oxygenation levels. However, They are extremely adaptable and can easily tolerate temperatures into the lower 80's. They have also been found able to tolerate saltwater up to 15ppt (1.011).

 

I would hesitate to trust what aquaculturists say because they are not in the business of providing optimal conditions for fish health. Just whatever makes the fish grow to market the fastest is considered ideal. They also have heavy duty equipment that can keep up with the increased metabolic rates and waste, whereas in a home aquaria that is harder to achieve.

 

Goldfish are studied a ton at the University of Washington as, unfortunately, they have become prolific in our lakes and ponds as people release them. While not huge predators of fish eggs, tadpoles, and fish they have huge appetites and can often outcompete other native fish for resources, such as aquatic vegetation. They have also found that goldfish over several generations tend to revert back to wild morphology which wasn't asked, but interesting.

[Odd Duck]

On 9/17/2021 at 6:59 AM, Barbvday said:

I have some serious concerns about some “advice” some people are giving in a very large fb group called Fish Tank Talk.

there are individuals that are advocating for use of heaters for goldfish based on some research that some guy found over the years. After skimming over it, most research was done on common goldfish and to see if they would prefer to be in warmer over colder water.

I am personally not a seasoned keeper of goldfish, particularly fancy goldfish but I know that there are negative long term effects for goldfish if kept at higher temperatures.

does anyone have any studies or research references to back this one up?

 

thank you.

The flaw in his premise is using the goldfish temperature preferences.  My dogs would prefer to eat lots of ham, but that certainly wouldn’t be healthy for them in the long run.  Can you say hemorrhagic, necrotizing pancreatitis?

The animals temperature preference should be taken into account, but the studies towards the bottom about “egg development”, and “egg and larvae viability” tells us a bit more, I think, about what is healthier.  The other studies about heart rate, growth rate, tell us very similar things noticed in other ectothermic species - growth rate and longevity are often inversely related with faster growth but shorter life span at higher temps (within certain range limits).

I suspect the answer will be determined by what you want for, and out of, your fish.  Do you want optimal growth and color, keep them a bit warmer.  Do you want optimal lifespan, optimal egg and larvae viability, keep them a bit cooler.

[Kathy F]

My fancies are in an unheated tank but b/w the lights and 2 HOB filters, it actually runs hotter then my other tanks;   Currently running at 79 degrees.   They are fine and acting normal (some of them I have had for 3 years so I know their normal behaviors) so I have left the temp alone.   If they started acting distressed I would attempt to cool things down.    Weather here is starting to cool  so in another month or two their tank should naturally drop into the low 70s and not hit mid 70s until April or so.   

As far as growth rates, I will say that one inch baby ranchu I picked up 2 months ago has trippled and is now a 3 inch fish and the 3 inch fish I bought in spring are about to hit the 5 inch mark so they are growing rapidly.  I'm also doing frequent water changes 75% every 4 days to maintain water parameters. 

 

[PineSong]

On 9/17/2021 at 11:57 AM, Biotope Biologist said:

They have also found that goldfish over several generations tend to revert back to wild morphology which wasn't asked, but interesting.

Is this because once released they mate with other goldfish regardless of morphology, e.g. the released ranchu breeds with a comet and the ranchu traits are diluted, or is it that without vigorous selective/line breeding, the genes that produce the wild morphology increase gradually over time e.g.  even if you put 20 ranchus in a breeding situation and just let them breed with each other randomly, after X number of generations the offspring will be more like comets?

[Biotope Biologist]

I would assume without selective pressures being applied to them by breeders the expression of wild phenotypes would enable future generations to survive better as they are able to blend in.

 

I imagine breeds that are purely ornamental such as butterfly and telescope and ryukin would die quickly in the wild.

 

All of that is speculative as I can't find any research articles that explain the reversion to wild phenotypes, it was just noted by collectors. They also hybridize with Cyprinio carpio so that further muttles the gene pool and gene expression.

 

[GardenStateGoldfish]

On 9/17/2021 at 7:59 AM, Barbvday said:

I have some serious concerns about some “advice” some people are giving in a very large fb group called Fish Tank Talk.

there are individuals that are advocating for use of heaters for goldfish based on some research that some guy found over the years.

I would advise against heater use for goldfish, I can dredge up research and literature when I get home (in Virginia this weekend for a wedding) but goldfish are not cold water fish, but they are temperate, it is much healthier for them to go through periods of cold and periods of warm. Goldfish metabolisms are faster the warmer the water is, which means if you kept goldfish in warm water only, they need more food, more oxygen, grow faster, and live shorter and get larger. So lots of research says when farming or growing goldfish for sale, warmer water is best for sale, but it is not for health, Thai goldfish fall in this category, they are not as cold tolerant as Chinese or Japanese varieties and are very pretty, but generally have more health issues associated because of the quick growth to sale from warm water. 
 

Female goldfish need the period of cold water for about 6 to 8 weeks for healthy egg development and these periods of cold are very healthy for male and female goldfish and greatly lengthen lifespan. Keeping goldfish at a stable temp around 70 is like us on a 70 degree day, not to cold nor to hot, so that’s a great temp for them, but doesn’t elicit the natural cycle in their life. 
 

tldr ; warm water is beneficial but so is cold water, seasons are better than stable temp, If you can’t create a season heater for 6 months and no heater for 6 months is better, if you can get goldfish into the 50-60 range for 3 months it’s amazing for their functions and health

[Barbvday]

Thank you for the replies!

I completely agree with your statements and if you do get a chance I would love to get some literature.

 

have fun in Virginia!