Caresheet: Fancy Goldfish | Carassius Auratus




Fancy Goldfish

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After writing about them since the beginning of this blog a year ago, it’s about time for an official fancy goldfish caresheet. These fish are the victim of many fishkeeping myths – they cannot actually live in fish bowls, they don’t actually have a short livespan and fish flakes aren’t a fantastic idea either – so it’s time to smash those!

Keep reading if you’re interested in buying a fancy goldfish or if you want to know how to better care for your fish.

Minimum tank size20 gallons (75 L), long, per fish
Temperature62-71 °F (17-22 °C)
LengthUp to 10″/25 cm
Everything you need to know about keeping fancy goldfish!
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Carassius auratus, fancy goldfish, fancies

Fancy goldfish natural habitat:

None, fancy goldfish are not found in the wild. Their wild ancestor, the Prussian Carp, is mainly found in Asia.

Fancy goldfish appearance:

Fancy goldfish are available in countless shapes and forms, but the different varieties have a few things in common. They are rounder than common goldfish and have double tails, that are usually long and flowy.

Fancies come in all colors and patterns – regular orange is most common, but more exotic color varieties like panda, chocolate and lavender can also be found. What fancy goldfish are most loved for, though, are the interesting appearances that have resulted from selective breeding.

Big, bulging eyes, brain-like tissue on the head, enlarged nasal bouquets, dorsalless fish, nothing is too crazy. Subtypes range from quite similar to common goldfish to very extreme. For more information about fancy goldfish varieties, check out this article.

Determining the gender of your goldfish can be quite a challenge, but it is possible. Males will often grow small white bumps on their pectoral fins and operculum; these are called breeding stars or breeding tubercles.

Fancy goldfish requirements:

Fancy goldfish requirements may surprise some fishkeepers – they have a reputation for being ‘beginner fish’ that can live in small tanks or bowls, which is unfortunately not true. Why goldfish bowls should be banned contains a more thorough explanation of why bowls are actually not suitable at all.

Fancies require about 20 gallons (75 l) per fish, frequent water changes and very heavy filtration. This is necessary because they are grow very big and produce a lot of waste – in smaller tanks, ammonia levels will get out of control very quickly, which results in health problems and stunted growth. A rectangular aquarium is preferable, as it allows for more oxygen to enter the water.

As for filtration, an external filter with room for biological filter material is the best idea – try to go for a filter rated for at least twice the size of the tank. I used an Eheim Classic for my 60 gal (240L) goldfish tank, which works fantastically when paired with a powerful internal filter. You can find a review of the Classic 250 here.

Good filtration will help keep the water values under control, but water changes are still necessary. Change at least 50-60% a week if you’ve followed the “20 gallons/75L per fish”-rule.

Decorating a fancy goldfish tank

Because most fancy goldfish are quite clumsy, it’s a good idea to avoid sharp rocks and decorations. Sturdy plants like Java fern are a better idea. Goldfish will try to eat most plant species, but this one will almost always be left alone. If substrate is used (I personally prefer not to), go for sand instead of rocks or gravel.

Goldfish love digging around the substrate and gravel can get stuck in their mouth, which can cause suffocation! Sand is also much easier to keep clean, especially if you use a thin layer of filter sand. Play sand should never be used, as it rots easily due to the forming of anaerobic pockets.

Fancy goldfish tankmates

Goldfish are very social animals that should never be kept alone for extended periods of time. Being alone makes them feel unsafe and vulnerable, which can cause unnecessary stress, so go for at least two goldfish.

As for other tankmates, there aren’t many options here, unfortunately. Many people keep their fancy goldfish with tropical fish like guppies and mollies or subtropical fish like danios, but I personally don’t recommend this as the tankmates may either be eaten or one of the fish will suffer due to the difference in temperature requirements (goldfish should never be kept in tropical aquariums). Fancy goldfish and their single tailed cousins are also usually not a good combo, as single tails are much faster and may outcompete the fancies for food.

The only tankmates I’d recommend are snails like ramshorn or Nerite snails. These often do a great job at algae eating and won’t be bothered too much by the curious goldfish.

Fancy goldfish diet

Time to smash another goldfish myth here! Though not all flake food is bad, the cheap “goldfish flakes” that can be bought at any pet store are not actually good for your goldie – they don’t contain the nutrients it needs.

For a healthy goldfish it’s a better idea to go for a varied diet consisting of a staple pellet (I feed Hikari Staple), blanched veggies like zucchini, peas and kale, and frozen/live foods like bloodworms, brine shrimp or mosquito larvae. It’s also possible to make your own goldfish gel food.

Divide the food in small portions throughout the day. I aim to feed my goldfish at least 3-4 times every day – pellets once or twice a day and veggies and frozen foods the other times. If one of your goldfish outcompetes the others when it comes to food, try feeding in different places at once or feeding floating and sinking foods at the same time so they all have a fair chance.

Fancy goldfish behavior

Fancy goldfish are endlessly fun to watch due to their behaviour and personalities. They’re curious, silly, clumsy and very enthusiastic – once they get used to someone regularly feeding them, they will start begging for food whenever anyone enters the room.

Silly as it may sound to some, many goldfish keepers feel a real ‘bond’ with their goldfish that can’t be achieved with most tropical community fish. Fancies all seem to have their own personalities, which makes them perfect for anyone who is a bit bored of regular community aquariums.

Goldfish are usually friendly and peaceful towards each other and like to stick together and follow each other around most of the time. During spawning time more ‘rough’ behaviour may occur: males will start chasing the female around in an attempt to force the eggs out. This can get a bit ugly especially if you have more males than females. Keep a close eye on them and temporarily separate the female if she seems too stressed.

Breeding fancy goldfish

Breeding fancy goldfish is quite a challenge, and although it can be very interesting, it’s not something to be taken lightly. If you want to breed your fancies, be prepared for endless water changes and possibly having to cull deformed/sick fry.

Once the fish spawn, usually on stem plants like anacharis or on spawning mops, the eggs should be removed as quickly as possible (or they will be eaten before they can hatch). A small barebottom aquarium with a (small) air pump and a heater set to ~76-78 °F/24-25 °C is a good place to keep them until the fry are big enough to be moved to a bigger tank. Be sure to check on the eggs regularly and remove ones with fungus on them to prevent it from spreading.

Newly hatched fry have a yolk sac they can feed on for the first 1-2 days; don’t disturb them during this phase and don’t start feeding yet, as this will foul the water. When the yolk sacs have been absorbed, you can start feeding. A special fry food is easiest, as the fry are too small to eat most other foods. Keep the water in the fry tank level low (4-5 inches/10-13 cm) until the fry stop clinging to the bottom/sides all the time. This helps them develop their swim bladders more easily.

After the first week you can start doing water changes (at least 100% a day) and increasing the amount of food; feeding 5-6 times a day is necessary to ensure the fry grow well. Newly hatched brine shrimp or ground brine shrimp usually work best in this stage. You can also start picking out the fry that are obviously deformed or sick; look for bent spines, fungus or missing parts. It may be hard to cull these deformed baby fish, but they will suffer and eventually die if you don’t.

After a few weeks it’s time to switch the fry to a bigger, filtered tank or Sterilite tub. Clean the filter daily and continue doing daily water changes; cull any fry that seem deformed (look at the mouth as well) or that show unusual behaviour like bottom sitting or floating.

Breeding fancy goldfish is something to take seriously! If you’re not sure, don’t try it.

If you have any more questions about fancy goldfish or if you think I forgot to mention something in this caresheet, don’t hesitate to leave a comment below!

Other goldfish-related articles on Aquariadise:

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15 thoughts on “Caresheet: Fancy Goldfish | Carassius Auratus”

  1. Hi Mari! Sorry to ask you again, but why are there weird green seaweed-like small “plants” growing on my tank? Thanks! And sorry because I forgot to ask you this!

  2. Hi. I own 2 two finned goldies. They live in a 19 litre tank (square). And there pretty happy. After a year or two, one of them started to be less active. Could you help me out?

    • Hello,
      It sounds like your aquarium is much, much too small for your goldies unfortunately. Although they’re very strong, there’s a good chance the bad water values that too little water volume causes has started to catch up with this one.

      If you’d like to sustain your fish in the long run you’ll have to upgrade them to a larger aquarium as discussed in this caresheet. Otherwise, things will unfortunately continue to go south. Have a look at this picture if you’re unsure why I’m saying this. The aquarium in question is 60 liters, 3x as big as your tank. The fish just get too big for a tank this small, the minimum is 80 liters per fish.

    • I lost my rykin after 3.5 yrs to swim bladder tryed to save with peas bath in Epson salt she lie there fought to swim to top made it but could stay on top eventually passed away. She was smart happy ryukin grew a long fantail. Can’t stand it feel that I failed her. Name was Melissa roommate nicknamed her swimgirl. Hope I meet her again n wherever she is Melissa can see this love her so much

      • So sorry to hear this 🙁 sometimes there is just nothing you can do. It seems like you tried everything you could.

  3. Hi there,

    Great article! I’m really impressed with the depth of information that you’ve presented here. There are so many myths surrounding goldfish care which need to be cleared up. I second the motion that fish flakes are not a good idea, and find it upsetting that they are the number one selling goldfish food in pet stores. Again, thanks for sharing this resource everyone needs to hear. 🙂

  4. Hello! I have a couple questions:

    I’ve had an oranda for over a year now — it may be close to two years — and I’ve followed every piece of advice/information I’ve found through your Tumblr. I have him in a what I remember as a 37 gallon tank that I usually just round off to 40 (hopefully that’s not a bad idea???) and unfortunately he is alone because I don’t want to crowd the tank with another oranda (and even though you mention that 20 gallons is okay for one oranda, obviously I don’t have 20, technically, and I’d want plenty of room for both). I would LOVE to get another one, and I plan to once I can afford a bigger tank, but now I’m worried he’s lonely! D:

    I’ve saved the link you provided for the filter you use, and I wanted to ask what kind of media you use in it? Right now I don’t have a cannister type filter but I am definitely going to upgrade asap. The filter I currently have is meant for a 75 gallon tank, if I recall correctly, and I do weekly water changes.

    Otherwise I think I have everything down. I feed him pellets and peas for the most part, and am in the process of introducing shrimp. I’m sorry if I’m rambling, I just want the best for him! If anything I’ve said raises a red flag for you PLEASE let me know!

    Thank you!

    • Hello!
      You seem very invested in caring for your oranda correctly, so refreshing to hear!
      I agree on not introducing another goldfish, at least not until you have a canister filter, as you technically probably only have around 35 gallons to work with. If you’re interested in getting a bigger home for your oranda without spending too much, try checking out sites where you can buy aquariums used. You can also go for koi bowls/round ponds like I did; I got a 55 gal with a very big, strong pond filter for around $50. I’d advise you to not wait too long, as goldfish are group animals that do get a bit lonely when kept on their own. If you do introduce another fish, try to get it from a professional breeder and be sure to quarantine!

      The Eheim filter I used (I have a big pond filter now) came with media. It contained a bag of biological filter material, two types of sponge and filter floss on top, which is ideal! I just love external filters, as biological filter material is so so so important to keep things balanced in your aquarium. They also don’t take up any space inside the tank.

      I always recommend feeding goldfish frozen foods like brine shrimp, mosquito larvae or bloodworms a few times a week, as they are omnivores. If you’re not already doing that, definitely something to try! I’d also skip the shrimp if you haven’t introduced them already, goldfish unfortunately eat everything that fits into their mouths and shrimp are definitely no exception.

      Good luck with finding a new filter and eventually maybe a second fancy! I’d love to hear updates.

      • First off, thank you so much for responding. Literally a day after I sent my message to you, I noticed my fish (Colossus) was turning over on his side and floating. 🙁

        My last oranda died from swim bladder. It progressed so rapidly that he passed away within 24 hours. Although I did a water change and offered him peas, he wouldn’t take them.

        It’s been a week now and he’s still doing okay, despite the buoyancy issues. I did a water change immediately after I noticed it, added some aquarium salt, started feeding him peas, changed the water again yesterday (as it had been seven days) after fasting him for a couple of days and gave him peas again. I noticed some green poop a couple of days ago, but he’s still floating, and I’m not sure what to do from here. 🙁

        I messaged a couple of people who also run goldfish blogs and no one has replied.

        I don’t know what happened. I’ve been slowly taking out the gravel in his tank over the last few months after finding out that gravel is not the best substrate for him, have added a couple live plants, have kept up on water changes, feed him decent food(s) (mostly veggies and sinking pellets which I soak beforehand) and I planned on buying the canister filter you suggested with my next paycheck.

        I’m sorry if I’m just bothering you with this, but I’ve scoured the internet looking on how to treat it. Is it pretty much hopeless at this point?

        He’s still very energetic and every time he turns on his side he fights it, but I don’t know if that’s necessarily a good thing.

        Thank you again. I really appreciate it.


        • So sorry to hear about these problems. Don’t worry, you’re not bothering me (if I didn’t want to try to help people out I would keep the comments closed), but it’s very very difficult to help without actually seeing the fish/setup.

          Swim bladder issues are one of the most difficult things to deal with because there are so many different possible causes. It’s usually a symptom, not an actual disease – it can be caused by bacterial infections, parasites, bad water values, stunted growth, constipation, etc., etc. I recently had to euthanize my own oranda because he had chronic swim bladder issues due to stunting, so I know how shitty it is to see your fish on its side/upside down. I’ll try to list the other symptoms of some possible causes, maybe you recognize one of these things.

          You mention keeping up the water changes. Do you also keep a close eye on ammonia/nitrite/nitrate values (with a drop test kit) and the water temperature? If ammonia or nitrite are above 0 ppm it can cause all kinds of problems. Nitrite spikes can be recognized in fish from red streaks in the fins and Ammonia causes black burns/patches. High nitrate levels can cause weird swimming, although the chances of this seem small to me with all the water changes.

          Another possibility is bacterial problems, which is a bit more difficult. Have you noticed any finrot, pop-eye, pineconing, abscesses etc.? If bacterial infection jumps to the swim bladder it can cause instability. Bacterial problems are caused by bad water quality and/or a damaged immune system.

          Parasites can affect the swim bladder as well – do you see your oranda flashing/scratching/making sudden movements? My oranda was pretty unstable when he had parasites.

          If you’ve been fasting and feeding peas, I don’t think it’s constipation/food allergy. I also suspect it’s not stunting. I would not continue with the salt for now – only add it if you’re sure it’s necessary.
          I’m really sorry I can’t help you out more. Hopefully a water test will clear some things up. If not, you could consider posting in Koko’s Goldfish’ Disease & Diagnosis section; these people have much more experience with fancies than me and they know how to help you out.

          Good luck with your oranda. Keep me updated!

          • Hi Mari,

            I’ve been checking my levels frequently, and despite my numerous efforts, he started getting worse yesterday afternoon. I decided it would be best to put him down, so I did that today after much hysterical sobbing.

            Thank you for all your help and advice. I will be sure to come to you once I feel it’s the right time to begin a new journey with another goldie.


          • Oh no 🙁 I am so so sorry. I wish I could’ve helped you out more.

            I hope you won’t let this scare you away from the hobby. You did all you could and you clearly cared about him a lot. Once you feel ready to get a new goldie, feel free to contact me and I’ll try my best to help you prevent this from happening again.


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