My Experience with Indoor Goldfish Keeping

  • #1
For those who have thought about getting a fancy goldfish tank. This is my limited experience with canister, HOB/sponge filtration only, no sumps. And my tank is 40 and 75.
-- I have not and would not support keeping single finned common goldfish in a tank, they are pond fish, large ponds.
-- This is just my experience and what has worked for me to have health goldfish that aren't sick or stunted and thriving. Unfortunately I have killed goldfish, maybe this will help someone get an idea so they don't kill expensive goldfish.

It's a lot of work. But compared to keeping dog etc, still less work. Every problem I've seen when it comes to goldfish problems have been because goldfish keeper is lazy. One thing I have learned, majority of the youtube videos and Reddit on goldfish is fish abuse. Goldfish feed and forage constantly. It's recommended a goldfish feed 2% of their bodyweight per day, which I do with Repashy. Almost every video or pic of goldfish I've seen outside of SouthEast goldfish keepers, have been stunted or starved goldfish.

As one veterinarian I saw vid on basic fish keeping said, fish should not be starved or abused because a fishkeeper is too lazy to upkeep their environment. The #1 reason why goldfish are stunted and starved is because people don't want to do the weekly to bi-weekly water changes, and large water changes. They don't want to maintain their filters. If you're not willing to do the weekly and frequent maintenance, don't get goldfish.

One thing I've been annoyed by is people showing images or videos of the growth of their fish after 6 months or to a year and seeing their fish have only grown what should have only taken 1-2 months. It's pathetic people think these are good growth, and it's not, remember these fish grow to 8-10 inches and it's not just length but girth. Don't be that a*hole just because you're lazy.

I enjoy my weekly maintenance. I really don't find cleaning the tank, changing water weekly and doing monthly filter maintenance a lot of work, but it would seem there are incredibly lazy fish keepers out there.

Water Temp: Goldfish are found as invasive species globally, everywhere from Nordic waters to Amazon River. So yes they are adaptable. My recommendation? Ask your dealer, they know where the goldfish is from, how they were bred. Just go with their recommendation. All my goldfish are from Thailand and SouthEast China, I keep the water warm.

Don't overfeed your fish BS: One thing I've learned most people who claim this, are lazy fishkeepers. This really has more to do with laziness and wanting crystal clear water without doing the work than health of the fish. This is for planted tanks too, concern for algae growth. If you got too many fish and not enough plants, that's YOUR problem, not the fish, don't be an a*hole. Underfeeding is worse than overfeeding. If you are feeding adequate amount, then just need to keep up with your tank maintenance. You see the youtubers who give advice for crystal clear water? Their number one advice every time is about feeding, and that's cause these are the same people who are too lazy to clean their filters more than once a year. If you look at their cichlids, they all got sunken bellies, they are all underfed. Goldfish? Same, sunken bellies or stunted growth. Don't keep goldfish if you're too lazy to do upkeep and resorting to underfeeding.
-- We keep fish in tanks for our own enjoyment, it's not ideal. Feed them what they need, don't underfeed because what we are doing is already selfish, and desire for clean water, crystal clear water and underfeeding is wrong.
-- Remember, it's recommended for all fish 1% to 2% body weight per day. Remember not having a crystal clear water or algae problems if YOUR problem, not the fish, don't abuse the fish.

Cost: Just get the right setup first. Don't make the excuse it will be grow out. That's BS, and it leads to above, stunted goldfish. I'd say get the largest tank you can, but from all long term successful keepers, the minimum is 4 feet wide tank. It's what I went with, I know, I have the minimum recommendation.
-- It's far cheaper to plan out your tank and get what you need the first time rather than upgrading. Don't bother with the 40 breeder because it's a great deal during Petco sales. You can get the 60 breeder which is 4 feet wide and 18 inches deep if cost is an issue, but I would get the 75 just because water volume matters with goldfish.

-- I initially tried using sponge filters, rubbish. The bio-filtration was excellent, but you need A LOT of them. And with more sponge filters, the noise is infuriating. And it resulted with piles and piles of fish feces on the substrate. And the amount of waste when it came to clean the sponges, immense and disgusting. Just keep it in a canister.
-- Simple vs Complex canisters: Fluval and Oase for goldfish keeping are trash. Don't bother, they are overly complicated. The FX series are the worst, stupid water flow system, overly complicated trays, and incredible small volume of media capacity to their size. Look for something that can hold a lot of sponges, large trays, with simple water flow, easy to maintain and clean. I highly recommend canisters like Sicce Whale/Eko, SunSun types, Eheim classic, or if you got the money, the Fzone. Tons of sponge, easy to clean. Keep it simple. Complicated don't work with goldfish, too much waste, you'll be cleaning the Oase Pre-filter every week. And complicated like Fluval with small trays for biomedia, rubbish.
-- HOB are noisy with the constant splashing sounds, and they don't have the capacity or flow to keep tank as clean as I wanted and elminate waste as fast as I wanted. AquarClear are the worst HOB IMO with what's available now. HOB also don't allow for much control in flow, and that was a big thing for me, how to direct water flow, HOB don't allow for that.
-- Sump, if you can do it, I'd recommend it. I don't have experience with it, but it's evident to me it's the superior filtration system, but I don't want to listen to splashing water all day, night.

Best Biomedia for Goldfish?
-- What's the best biomedia? Sponge. That's it. I've found nothing works better than sponge. The goldfish are constant poop machines, sponge filtration cleans up the tank for that swimming in air look appearance and keeps up with their bio load the best. Don't get fooled by lava rocks, pumice stones, ceramic rings, biohome etc, I tried em all, nothing works better than sponge for static biomedia. I went with Swiss Tropicals Porex, it's not much more than sponge from Amazon but I've found they don't compress or deform over time like Amazon ones.
-- Do your research and you'll probably find what I found. None of the specialty ceramic, sintered glass or pumice stone manufacturers have any evidence to back up their claims. The only scientific evidence and tests I've seen show that sponge is the superior biomedia. The rest are based on hearsay.
-- Your goldfish don't care and your tank don't care how much surface area or film MarinePure claims for example, because sponge actually wins on both since some of the pores in MarinePure types are not accessible, they are just holes inside, try cutting a MarinePure media in half open and you'll see it's pores don't go all the way through, sponge does.

Nitrates: Don't bother chasing the zero nitrate filtration for goldfish. Instead focus on good and regular maintenance of your tank instead, just ignore nitrates is even a thing. I have zero nitrate tank with my planted 20, and that's the key, planted, plenty of fast growing plants. I've found the durable plants that can withstand goldfish do not grow fast enough to eliminate all the ammonia and therefore keeping nitrates down. I found porthos and house plants really don't do much other than make your tank ugly. Porthos do not suck up nitrates like people think they do, a little, but not enough to impact a 75 gallon with goldfish, what they do is consume ammonia, therefore eliminating the nitrogen cycle that produces nitrates, but your filtration already does that. My nitrates did not go down with house plants and plants that can withstand goldfish are too slow growing to impact nitrates. The only time where plants seem to work are people who have plants with large amounts of terrestrial plants or large floaters like water hyacinths and huge growths of hair algae.
-- I'd be interested if someone here has experience with green carpeted hair algae and whether that impacts nitrates, I suspect it would, but I don't have interest in green carpet algae, seems like a lot of work.
-- I've found weekly water changes are required for overall quality of the water anyway, regardless of nitrates. So this is a non-issue
-- Also discovered the goldfish breeders from South East Asia where the highest quality goldfish are from, they often have high nitrates in their water source to begin with. Goldfish appear to be used to high nitrates.

Ammonia/Nitrites: The idea that goldfish are hardy fish that can withstand poor water quality at least for fancies is a myth. At the very beginning I tried to in-fish cycling and it was tragic. Without plants to consume the ammonia like I had with planted tank, it doesn't work well. Once you start seeing red streaks on the goldfish, better start medicated foods, doxycycline is the recommended, as your fish now likely internal infection in the blood. Don't be destroying your filtration medicating entire tank, because you're going to be destroying your bio-filtration which is the reason why your fish is sick to begin with. You heard it before, if you got a sick goldfish, maintaining and fixing your water quality is your #1 priority. I do think goldfish are hardy in that if you provide excellent water quality, they will recover and heal. Almost everything with goldfish I found leads back to filtration and laziness. If you do fish-in cycling, you better be prepared to be doing 50-75% water changes daily, sometimes twice daily until it stabilizes. Using sponge will help, don't bother with the scam biomedias, sponge cycles the fastest and works the best to reduce ammonia, nitrites.

UV: Does it work? I dunno, I use it anyway. Whether you choose to use UV or not, up to you, I use the Green Machine 24 watt as it has enough power and slow flow to kill parasites, and bacteria, I'm not really concerned about algae.

Ranchu Goldfish need shallow tanks myth: This is a myth. Ranchu were popularized in Japan and then later imported and developed in China the 1980s (Chinese Ranchu is recent breed). This myth was because these were top down view fish, kept in shallow bowls or shallow ponds meant to be looked down. It's not because the Ranchu don't do well in deeper tank like 75. They do fine, they are fine. I traveled in Hong Kong and saw enormous tanks, very deep tanks, monstrous tanks filled with Chinese Ranchu and they were fine.

Goldfish can't deal with current flow myth: Another myth. These fish are actually good swimmers. First rule of getting a goldfish, look for one that can swim, get a strong swimmer. Don't bother with a fish that can't swim. This of course within common sense, you're not going to have flow like African Cichlid tank. Adjust your tanks flow to ensure enough water movement to maintain water clarity, remove feces from the substrate, and fish will be fine. I don't think it makes sense to support goldfish breeders who produce fish that can't swim.

Bare bottom tanks are cruel: Nothing worse than a bare bottom tank for goldfish. They are foragers, don't be cruel just because you're a lazy cheapass with garbage sponge filters and too lazy to vac your substrate. Have the proper filtration system to keep your tank clean and provide those foraging cows keep them happy. Now you don't have to go with substrate, if you can develop, maintain and grow algae carpet, that's awesome. Just an FYI for algae carpet, you're going to want to get grow lights or Aquarium Co-Op has cheap planted tank lights. Brown algae and other algae thrive in lower light, green hair algae love high lighting.

Don't buy sick or injured fish: You may want to be their savior, but it will likely result in having a difficult time with perpetually sick goldfish or dead goldfish. It's not worth it. Look for healthy goldfish that can swim well, that don't tilt on either side. Look to see they have even full fins, fins on both sides equal. Look at the bottom, make sure their bottoms are even, you'll be amazed at how many goldfish have uneven abdomen that lead to swim bladder issues, swimming problems, tilting etc. Spend the extra time to look at the goldfish, look for high quality videos and high quality pictures, look for dealers who are honest about the condition of the fish.

Swim bladder? This has not been a problem for me. I keep my water at 75-78F, and I feed them bloodworms, Repashy Gold or I soak the pellets for 10 min prior.

-- Petco/PetsMart have poor quality goldfish, most of them look sick, malnourished. Remember goldfish are going to require a lot of time, expenses on your part with food, water changes, electricity costs for filtration etc, it's not worth it have your tank as a rescue tank. Get the goldfish that will make you happy and make your tank look amazing.
-- Local fish store: they aren't much better than Petco tbh.
-- Goldfish Island: These are high volume dealers. Yes their fish are much higher quality than Petco and your local fish store, but they aren't as honest about condition of their fish. They show some videos and pics but not always easy to tell if the fish have deformities etc. And they price them same regardless. It's a gamble with Goldfish Island. I have great fish from Goldfish Island, but I always received a fish that had uneven abdomen, that tilted and swam in circles.
-- Chu Chu Goldfish: Can't say enough good things about them. Honest dealers, they will discount a fish if it has problems and they will tell you about it, I don't recommend buying those though. But they have much lower volume and IMO each goldfish is much higher quality than Goldfish Island. The irony is their pricing is much better as well. I believe Chu Chu only sell quality fish, they aren't about selling high volumes. It may take a while for them to stock the fish you are looking for from them.
-- Zhao's Fancies: These are bred by Zhao, they are amazing fish. His pricing are great. And his photos and videos are best among the online dealers. Can't go wrong with Zhao.

I'd say if you are interested in buying high quality Thai goldfish, go with Chu Chu. If you want high quality Chinese goldfish, go with Zhao's.

Food: I think this is personal and go with whatever works for you. I'm too lazy to constantly soak pellets so they sink properly. I've noticed most pellets are filled with air, soaking them I see bubbles releasing for example.
-- It would seem goldfish feed a lot of vegetative matter, algae, plants etc. So I would suggest foods that are high in greens. Recommended protein content is 32-35% and almost all food meet that, you don't need the high growth pellets with 50-60% protein for example.
-- Repashy works well for me as I'm lazy. I cut it and throw it in the tank, I don't have to weigh or soak the food.

Repashy weight to water ratio: I found 0.5% - 1% of goldfish bodyweight in dry powder comes out to right amount of food. For water, it's x4.
You weigh your fish, comes out to say 500 grams and do 0.6%.
3 grams in dry weight per day * 6 days = 18 grams. 18*4 = 72 grams of water.
I boil the water and just pour into the container with a scale until I get 18+72 grams in weight. And then divide into 12, as I feed twice a day.
-- If you do 1% prob looking at doing 2-3 water changes a week, it's a LOT of food.

These have been my experience and observation. Like I said, goldfish are great, but don't get them if you're lazy or underestimating the work required. Large weekly water changes and monthly filter cleanings. Don't be that person who abuses their goldfish because too lazy to clean your filter.

  • #2
I don't disagree, but this isn't really just goldfish. this can be applied to any fish really or anyone that overstocks, but then doesn't want to water change, and doesn't like the $20+ a month food bill and then cuts corners or gets lazy or "tightens the belt" on the fish being kept.

Goldfish are incredibly resilient, to a fault, they can really take some abuse and keep on kicking, which is kinda sad when you think about it.

WAY too many people get into the fish keeping hobby with the wrong mentality, that it will be easy, or they won't mind because it's "just a fish" then they do things to a fish they would never dream of doing to a dog or cat because it would be animal abuse or neglect.
not much protection out there for fishies....

I appreciate you trying to spread the word and awareness of the responsibility. Just unfortunate we kind of have to wait for people to come to us with their problems when they have had enough of the fish dying and give them the hard truth, that their care leaves some to be desired as a big first step into doing it right.

  • #3
Thanks for the write up. Sounds like your describing fish keeping in general. Maybe Goldfish get more abuse because of their cultural place as a throw away fish (in the US), but then, fish in general seem to be treated much worse than other pets.

As mentioned, their adaptability (like bettas) probably sets therm up for abuse as well.
  • #4
I’m of the firm belief that the best first pet is a dog or cat. Why? Because they can tell you what they need. And can’t really be ignored that easily. There’s less misinformation and abundant sources on how to properly care for them.

And people still think delicate, skittish, exotics are a better first pet.
  • Thread Starter
  • #5
Can't update my post:

But update for filtration. Don't use 40-45 PPI foam or you'll be doing canister cleaning every 1-2 weeks.

After speaking with Swiss Tropicals, it was suggested half 20 PPI and half 30 PPI or just do 100% 20 or 30, whichever works for you. I have since switched today and will see how it goes.

Also it's recommended not to do thorough cleaning, just rinse them. It's been shown thorough cleaning of sponge will just reset the biofiltration. Hopefully I'll have better results with this change. Good luck all.

Substrate Option: Green Carpet

-- I've also since changed to green carpet algae instead of sand substrate. Why? I'm not gonna try a planted tank with goldfish, as I rather have more open space for the fish to grow as 75 is prob borderline in size for 3 fancy goldfish. It only took a few weeks, but I now have carpet algae on the bottom and side of one and the goldfish continue to graze and pick at the algae, and from their feces can clearly tell they eat quite a bit of it. So a food source, something for them to do and it's been keeping my nitrates down to negligible and I now just do 50% water change once a week. Seems to be the best option for my needs.

I still think doing a straight bare bottom tank would be cruel, but the algae gives them something to graze on, seems like an OK compromise.

I have since learned that traditional goldfish keeping doesn't use any filtration and obviously air stones.

How did they do this? Algae and green water.
  • #6
Just get the right setup first. Don't make the excuse it will be grow out
This is the most important advice ever.
My opinion is you can Only call it a grow out tank if you already own the larger tank you plan to move the fish into.

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