Goldfish Care Sheet

  • #1
Goldfish Caresheet


Hey guys I would like to add a care-sheet on goldfish, hope it will help everyone. U can add your suggestions here, please. [Neville]

Huge waste producers

Goldfish are heavy waste producers [Neville]


Do not overfeed them or they will die, because they have a poor digestion system, give them food only they can consume within a minute; twice a day.

Feed them sinking food, or pre-soak the food in a separate bowl in tank water. Giving them floating flakes puts them at risk of developing a swim bladder disease. [Armadillo]


Best tank mates for a goldfish is other goldfish. don't keep them with fin nippers like barbs. [Neville]

Goldfish are long-finned slow movers, have big mouths, have specific temperature requirements and are huge polluters. This makes them unsuitable tank mates for any:
tropical fish (temperature requirements)
faster fish (most fish are faster, that includes seemingly innocent cleaner fish such as butterfly loaches)
small fish or inverts (goldfish could swallow them easily)
In other words, keep goldfish with... goldfish. [Armadillo]

Larger freshwater minnows seem to get along well with my goldfish and do a good job of eating what the goldfish miss.[michaelb323]

A couple of options for tank mates for goldies are mosquito fish (or other small temperate water minnows) and American Flag Fish.[gremlin]

Temperatures under 10C and over 25C are detrimental to the goldfish. As are sudden swings in temperature (e.g. unheated night/day difference, on-off air conditioning). A heater keeping the temperature at a steady 22C is recommended. [Armadillo]

Also, it's not so much that goldfish need cold water, it's more that they don't need heating, and prefer seasonal shifts in temperature. Goldfish even do well in summers when their water reaches 80+ degrees. [Sirdarksol]


pH 6-7.5 [Neville]


Grows up to 6" or more [Neville]

'Goldfish may grow to a maximum length of 23 inches (59 cm) and a maximum weight of 9.9 pounds (4.5 kg)' ) [Armadillo]

Light regime

Keep the lights on for 8-10 hrs only, goldfish rest at night [Neville]

Volume recommendation

Contrary to popular opinion, goldfish need space and filtration. [Sirdarksol]

A well recognised estimate in the hobby is 20G for the first goldfish, and an additional 10G per additional goldfish. This seems surprising, but knowing that the possible lifespan of a goldfish is 20 years, their life in reduced volume could explain why such a lifespan is so rarely seen. A goldfish is a huge waste producer, and its growth will be stunted. [Armadillo]

No kind of goldfish can go in a small tank for too long...they get really big. I had 8 fancy goldfish in 20g...they were tiny but once I learned more I realized with amount of goldfish I had at the time...we needed the 120 gallon we have now. So I sold them...I really didn't want a huge goldfish tank. [Allie]

Fancy goldfish should do fine with the 20 gallon for the first and 10 gallon for each additional goldie. However, the faster moving common, comet, and shubunkin goldfish need additional space. 30 gallons for the first, and an additional 15 - 20 gallon per additional goldie would be better. Also, they need room to swim and turn around as they can easily grow to a foot long (or more) within 2-3 years. Also, it is not a good idea to keep the two types of goldfish together as the faster moving ones will eat all the food before the slower fancy goldfish can get to it.[gremlin]

Goldfish and plants

Goldfish will eat your plants. There are only a few, such as java ferns, that don't interest goldfish. [Sirdarksol]


The main body of the care-sheet was prepared by Neville.

The care-sheet was standardized and edited by Armadillo.

Other contributors are credited next to their text in the care-sheet.

Want to add something?

We welcome additions to the care-sheet. To contribute a tip or warning, add a post to this thread and we will integrate it to the main body of the care-sheet with your name next to it. If you are quoting from a reference, please credit the author. [Armadillo]

*Accidentally deleted by Mike (Doh!) re-adding
  • #2
Tip: If you feed a quality food like New Life Spectrum pellets then there is no need to presoak the food. NLS food is very easy to digest and turns to mush within minutes of being eaten. []
  • #4
I have to add that soaking food removes all the water soluble nutrients like carbs
  • #5
Just would like to add my thoughts on this sheet for those who are interested. By and large the info is pretty accurate but there are a few things I would like to raise an objection to:

Starting with the "Huge Waste Producers" Label... actually goldfish do not produce more waste for their body size than tropical fish. That is a myth, people are just shocked by the waste load because they are used to guppy-sized poops. See Goldfish Myths Debunked for further explanation.

That they have a poor digestive system is also a label I would contend with. Perhaps the fancy body of the goldfish, being more compact as it is, makes food more likely to become impacted, but the actual digestive process is very efficient - when they are fed correctly. They are meant to be foragers in the wild, constantly eating in small amounts.

A pH of 6 is far too acidic for goldfish. It is recommended to be very near to 7.4, the same pH as human blood. They tolerate hard water much better than soft water.

This is a good care sheet about goldfish for beginners detailing some of the important points.

Anyway just wanted to share my $0.02,
  • #6
I strongly disagree with pre-soaking food. It removes a lot of nutrients. I recommend brands like Repashy Soilent Green, Omega One Goldfish Sinking Pellets, or New Life Spectrum Goldfish Pellets. Also, the biggest ever goldfish got 18 inches big, 23 inches is a huge myth, and very very very few exceed 12 inches, fancies get usually at most 5 inches.
  • #7
Edit: confused post. Haha.
  • #8
This may be outside the intended scope of the article but I wish someone would take on the subject of Goldfish Feeding; What Kind(s), How Much, and How Often in a more detailed and comprehensive way. Newbies, myself included, read all kinds of contradictory advice possibly applicable to different circumstances, but without explanation or elaboration. For example:
  • No bigger than an eyeball.
  • No more than they can eat in:
    • A few seconds.
    • Two minutes
    • Four minutes
    • Ten minutes
    • A few days. Usually said in connection with fresh vegetables
  • Two % of body weight.
  • Four % of body weight.
  • Body weight % is a fool's errand.
  • Large weights differences of various types of food. ie. dehydrated flakes and granules vs. gels and powder mixes.
These discussions usually warn against overfeeding because of:
  1. Damage to water quality,
  2. Obesity-related health problems.
  3. Digestive difficulties. Forum discussion of which invariably involves long quantitative and qualitative descriptions of poop:
  • Not enough poop
  • Too much poop
  • Wrong color poop
  • Wrong poop length
  • Etc.
It seems to me, these overfeeding problems are separate issues deserving, at the very least, separate complete sentences, if not paragraphs.

Furthermore, I think the nutrition labeling of fish food is woefully inadequate. They usually contain a percentage of protein and possibly fat but it shouldn't be very hard to show macro and micronutrients including vitamins and minerals and calorie totals. The software to do this in inexpensive readily available and easy to use. This part included in case fish food companies monitor these types of forums. Are you listening, Rapashy?
  • #9
Umm. I want one goldfish. I have snails though. And a 10 gallon tank. Would it still work?
  • #10
Umm. I want one goldfish. I have snails though. And a 10 gallon tank. Would it still work?
Did you read the care sheet? They need 20 gallons plus an EXTRA 10 gallons for additional goldfish.
  • #11
Yes.... I must have missed that.
  • #12
perhaps differentiate fancy and common/comet goldfishes.
This makes them unsuitable tank mates for any:
faster fish (most fish are faster, that includes seemingly innocent cleaner fish such as butterfly loaches)

and the temperature requirement should be updated to reflect that goldfish are temperate and not a true coldwater species. they are only called "coldwater fish" by aquarists b/c they don't require a heater.
This makes them unsuitable tank mates for any:
tropical fish (temperature requirements)

invasive goldfish in Texas (warm temperatures) List of fishes of Florida - Wikipedia

invasive goldfish in Brazil where many tropical fish come from/originated

invasive goldfish worldwide

"There are some significant implications in the range included in the introduced range of the goldfish. Throughout Indonesia and Malaysia it sits right on the equator. It also stretches continuously from India through the Middle East and into SaudI Arabia. Africa also shows their distribution within 30 degrees latitude. One of the most significant introduced areas is South America. Almost all of South America is now the introduced home of this supposedly coldwater species. This is not only significant in terms of latitude and temperature, but these are the exact same waters so many of the hobby’s tropical fish come from. Goldfish in the wild are literally swimming alongside the exact species kept in tropical tanks, and yet it is claimed to be too hot for them."

"There is even some indication of higher temperature being beneficial in multiple ways. It has been shown that pigmentation is increased with higher temperature. One study found that the ideal temperature for pigmentation was 26-30C (78.9-86F). (5) Pigmentation (coloration) is generally considered one indication of overall health and ability to thrive. In a different experiment it was found that the highest growth rate was at 28C (82.4F). (6) In both of these studies the ideal temperatures were found to be the highest temperatures used in the experiment. Since they did not use even higher temperatures it is unknown based on these experiments if even higher temperatures would have produced even better results."

another list of established and reproducing invasive goldfish populations around the world: Carassius auratus auratus (goldfish)

fancy goldfish bred and raised in the outdoor tropics like Philippines, Vietnam, Thailand, Hawaii, and Brasil

  • #13
I keep Clown Loaches and to my mind an adult Goldfish is similar in size (and other ways such as the need for company).

The recommended tank for Clown Loaches is 6' x 2' x 2' = 180 gallons.

Having seen fully grown Fancy Goldfish in the flesh this is the size of aquarium I would have for them.
  • #14
Yup, I just moved my ladies into a 75 gallon tank, I've had people tell me I could get 3 more in there! No way man, I MIGHT get a third fish eventually... I love seeing them with all that swimming space (and so do they!) Four foot long this tank is, they look so great in there
  • #15
I have to add that soaking food removes all the water soluble nutrients like carbs
I soak my fish food in a tiny bit of garlic water which can be added entirely. All of it, both Fish food and the garlic water. Then they don't miss out on carbs and such. Very very healthy for fish. There are many recipes for homemade garlic water/guard. My Goldfish have thrived on it, love it & let me know they don't like their food with out it. Respectfully everyone has a way that works for them. Happy fish hobbying to all!

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