Goldfish keeping doesn’t have to be difficult, frustrating…
A goldfish bowl can actually be a GREAT home for your little fish – if you use it correctly.
Using these secrets I’ve learned over the years, it can be enjoyable, educational, easy and FUN experience!
Tish, the oldest documented goldfish (43 years!) lived in a bowl its whole life!
The following methods all use some kind of filtration. Filtration is important to help your fish stay alive, unless you prefer to do daily water changes instead (which can lead to your fish quickly outgrowing your bowl).
This is a beautiful, hand-crafted bowl available in three sizes with openings from 4-6 inches, making it small enough to help keep goldfish from jumping out but large enough to allow for adequate cleaning. It is a sturdy weight and the glass is almost a quarter of an inch thick. The 10-inch bowl can hold just over two gallons of water. This bowl may have bubbles within the glass due to the handmade nature of the product, which adds to its charm.
Long and narrow build is preferred shape for active goldfish
If you’re in the market for a larger bowl for your goldfish, the Hygger Horizon 8-gallon is a great option. We know it isn’t a bowl per se, but we love it so much we couldn’t leave it out. This kit comes with a filter, LED lighting, and even faux rock décor. It does not have a lid but the LED light sits a couple of inches above the top of the tank. Due to the size of this kit, your goldfish may not need to be upgraded for a period of time as long as routine water changes are performed. The curved-front glass is sleek and the tank itself is long and narrow, which is the preferred shape of active goldfish.
This bowl option is a true stunner. It is crafted from handblown glass and real wood grown in Indonesia. Each bowl is unique in size and shape, but they hold anywhere from around one gallon to over four gallons of water depending on the inch size purchased. These bowls have approximately a 4-inch mouth. Due to the interior texturing of these bowls, they are a lovely option for plants and the unique design creates enrichment in a nano environment.
If you are torn on whether goldfish bowls are safe for your favorite fish and want more detailed information on the truth when it comes to proper goldfish housing, you should check out our best-selling book, The Truth About Goldfish, on Amazon. It covers everything about creating the most ideal tank setup and more!
4. Koller Products 1-gallon fishbowl with LED lighting
The Koller plastic fishbowl is a great option if you’re in the market for a smaller bowl. This may need to be upgraded to a larger bowl as the fish grows. This bowl has the clarity of glass without the weight and it’s shatterproof. It has a lid with LED lighting featuring seven different colors and a timer. The lid also has openings that allow for oxygen transfer, ensuring fish are able to breathe.
This is another lightweight, shatterproof option for small goldfish. Since it only holds two gallons, it may need to be upgraded as the fish grows. This bowl features a cool hex shape, making it a great option for a unique look. It has a small enough opening to reduce the risk of fish jumping out, but it is large enough to make it accessible for cleaning.
Magnetic lid for easy feeding and cleaning access while protecting fish
This futuristic-looking fishbowl features a hidden waterline, five-stage filtration, and multi-colored lighting. The lights are remote-controlled and have different brightness levels. It also has a lid with a magnetic catch, making for easy access when needed and keeping other curious pets out the rest of the time.
For small fish, this is a beautiful bowl option. This also works well in spaces without surface space available for a fishbowl. The hanging bowl will require frequent water changes for maximum fish health. This bowl works well as a planter and a shared space with a plant can help oxygenate the water for the fish.
Buyer’s Guide: Choosing The Best Goldfish Bowl
There are 3 main things to consider:
In general, the bigger the bowl – the better.
More water volume helps dilute the waste byproducts…
… and increases surface area for oxygen exchange.
Larger bowls allow more space to grow aquatic plants, which are INCREDIBLE for keeping the water safe for goldfish.
More plants = less work.
And they can support more fish.
From an aesthetic perspective:
Larger bowls have less distortion for viewing your fish than smaller bowls.
This isn’t as much of an issue if you have some kind of electric filter or airstone creating gas exchange.
Bowls that have a larger surface area (i.e. wider opening) for the water can support aquatic life better – especially when plants are being used as the only filter.
Thanks to better oxygen exchange.
You can also achieve a larger surface area by not filling the bowl up all the way to the top (if using a typical bubble style bowl).
You lose water volume which results in less swimming space for the fish, so starting out with a larger bowl can make up for this.
Sometimes the more unusual styles of bowls can actually afford great surface area for the size (even glass trifle or mixing bowls).
If using glass aquaria, thicker glass will be more durable.
Trust me, you will want this.
Glass that is too thin can burst without warning, harming your fish and your house and leaving a huge mess.
The bigger the bowl, the more important it is that the glass is durable.
4. Plastic or Glass?
Plastic containers are definitely the cheapest.
I even have one myself…
… but honestly prefer glass given the choice.
Plastic can leach chemicals into the water if heated which can harm aquatic life.
(The stuff used to make plastics can include glass fibers, mineral, flame retardants, colorants, release, silicone, formaldehyde and more – yikes! (source))
So while glass can be more pricey, it gives you peace of mind for the long-term health of your fish, especially if you plan on adding a heater.
The investment is well worth it.
A goldfish bowl is not only supposed to be an ornamental accent to your living area…
It’s perhaps the most fascinating and educational object you can have in your home!
How to Set Up a Goldfish Bowl
Tap the method below to see the instructions
+1. The Sand Planted Method
This is a very simple, reliable and safe method, which can be modified to your needs, and is outlined in the book Aquaria, A Treatise on the Food, Breeding, and Care of Fancy Goldfish, Paradise Fish, Etc. by Charles Nash Page.
I have used it for my own fish bowl setups with great success. My latest one has been going for about 6 months now with zero water changes and healthy, happy fish.
A self-sustaining bowl that requires very little maintenance.
(This means a little extra time in setup in exchange for way less work from then on.)
Ideally some scavenger snails (often come with plants)
Place roughly 1/2″ sand layer on the bottom of the bowl (more can be used if growing rooting plants).
Add a few shells (and pebbles, if desired) to the bottom.
Add any other desired decorations.
Slowly add 2″ of dechlorinated water and add plants (see recommend types below). Fill the rest with water.
Add your small healthy fish and place in a well lit area (not direct sunlight).
Why this Method Works:
Live plants readily remove ammonia and nitrite, as well as nitrate from the water keeping it safe for fish
Lime in the shells replenish alkalinity of the water, preventing pH crash
Good rooting plants include Cabomba, Ludwigia, Bacopa Monnieri (Moneywort) and Valisnaria. (Cabomba should be weighted down.) Hornwort is also a good nutrient absorbing plant that can float or be weighted down. You can get a bundle package of all these plants here which can be more economical than buying them all from different places online. Aerial plants are also very valuable for removing waste byproducts from the water and outcompeting algae. Good fish bowl aerial plants include dwarf water lettuce and duckweed.
Letting the plants grow in for a week or more is highly recommended if possible. This will allow them to better remove fish waste from the water.
Placing a 1″ layer of *sifted* organic potting mix under the 1/2″ sand will greatly assist in plant growth and prevent micronutrient deficiencies. It will also provide a stronger colony of beneficial bacteria. If you choose to do this, be sure to fill the water up very slowly with a plastic bag/lid and turkey baster to prevent popping the sand cap. If you use dirt, you do not have to add shells as the dirt replenishes the alkalinity. Epsoma is a good brand in my experience as I have gotten nitrates day 2 and no ammonia/nitrite.
Do not add too many shells or it will make the water too hard, which can harm plants/fish.
Adding several little snails to the bowl (ramshorn or nerites work well) will really keep the glass clean and plant leaves free of algae. Snails also help break down fish waste in your little ecosystem.
A screen is very useful to prevent cats and children from getting into the bowl, as well as prevent fish from jumping out. It’s easy to make these yourself!
Do not use gravel at the bottom unless you intend to use dirt underneath. Without dirt, the waste is trapped in the gravel and remains not broken down where it only fouls the water. Gravel can work well also but it needs the bacteria in soil to keep it safe.
It’s a good idea to give the bowl a few days without fish in it after planting to allow the plants to take root.
This style of bowl is very easy to maintain.
Thanks to the plants, regular maintenance only requires topping off evaporated water is necessary for water changes.
And if you make use of scavengers like snails, scrubbing algae is left to those who literally live to do it for you.
(Along with pruning the plants when they become overgrown, usually every month or two.)
Some people who are keeping goldfish in a bowl have a weekly routine of completely cleaning everything in it and removing all the water.
If it works for you, great.
To me, this can seems stressful to the fish and definitely more work than necessary.
Creating a miniature ecosystem keeps everything in balance and can result in a stable environment with long-lived fish.
+2. The Undergravel Filter Method
There’s another option for setting up a goldfish bowl if you don’t want to plant the bowl.
That option involves using a filter underneath the gravel to do the majority of the water cleaning.
The gravel becomes the surface for beneficial bacteria to colonize thanks to the gentle current of the filter below.
Undergravel filters don’t create so much current and simultaneously aerate the water.
Assemble the filter according to package instructions and place the bowl filter plate at the bottom of the empty bowl.
Fill the bowl with 1/2″ gravel (even better would be Seachem Matrix).
Optional: add a clump of hornwort (really helps go longer between cleanings). Place any other decorations if desired and fill with dechlorinated water.
Connect the airline tubing to your air pump and turn on.
Add your small healthy fish.
Why this Method Works:
A filter reduces the maintenance needed for your bowl so you can go for longer in between cleanings. It also allows you to add charcoal which can help with removing growth hormones from the water if your bowl is just temporary.
An undergravel bowl filter (I really like this one) is what will keep water moving through the substrate and allow better growth of your good bacteria colony. Personally I wouldn’t use any other internal filter on a goldfish bowl because it takes up too much room – or if it doesn’t, there isn’t enough room for the biological media.
The right kind will do something else very important… oxygenate the water.
You will want to keep the carbon going for the first 6-8 weeks that the bowl is set up if you haven’t cycled the bowl before you got the fish. (Yes, bowls can be cycled.) This will help protect the fish from high ammonia levels until the bacteria colony gets fully established. After that, you could remove it if you want to keep your fish small (carbon absorbs growth inhibiting hormones) – but you’ll want to keep the cartridge as I’ve found it really helps diffuse the current.
Keep in mind that this substrate will still need to be regularly cleaned to remove the debris and not with water containing chlorine.
Be sure the water level never goes below the top of the filter or it won’t work.
No messy of using dirt, plants are not a must.
It’s less work initially than setting up a planted bowl.
You can harness technology to help keep the bowl clean.
Floating plants can still be used if desired.
Unless you add floating plants, you miss out on the benefits live plants have to offer your fish.
Requires more equipment (air pump, filter, etc.)
No instant cycle as with dirt planted tanks, can require more maintenance
Cleaning is usually required every 7-14 days.
This involves the following:
Once a week 100% water changes is recommended (one partial water change mid-week is a good idea as well using a turkey baster or small siphon to remove debris from the bottom). You might be able to get away with going longer if you use a bigger bowl, depending on your water test results (ammonia always 0, nitrates should never go above 30ppm), however, the carbon should still be replaced weekly.
It’s a really good idea to age the new water overnight first with an airstone before you do your water change. This simple step will help gas off bad stuff from the water source. Don’t forget to use a dechlorinator first before aging.
The fish and any plants should be transferred into a separate container from their bowl water using your clean (residue-free), gentle hands. Remove the filter apparatus (if desired).
Use your hands to agitate the substrate around in the bowl, swishing it around well before transferring it to a bowl of fish water. Rinsing it with hot tap water can harm your beneficial bacteria colony you need on your substrate. If you feel like it is not clean enough, more water may be required. Any extra water you clean it in should be dechlorinated and aged overnight (such as in a bucket).
Dump the old dirty water on a plant or down the sink. Use a soft cloth (no soap) to wipe down the residue on the inside of the bowl.
Change the charcoal in the filter for fresh (it doesn’t usually last more than a week or so).
Replace the equipment and refill the bowl with aged, aerated water that has been previously dechlorinated. The fish can now be transferred back in by hand (the old water they were in should be discarded as well).
+3. The Sponge Filter Method
Sponge filters offer fantastic surface area for good bacteria to grow.
It does a fantastic job of aerating the water too!
You can use ANY style of fish bowl substrate or decor with this filter. Sand, gravel, plants, marbles… up to you.
Add your filter. Simply use the provided stones or put your media of choice in the bottom cartridge (i.e. carbon, Fluval BioMax or Seachem Matrix).
Fill with dechlorinated water & add fish.
Why it Works:
Filter provides biological (and optionally, chemical) filtration to keep ammonia and nitrite levels down.
It also aerates the water, providing oxygen to the fish
This baby is the smallest sponge filter available on the market and will fit in just about any bowl.
No need to worry about the continuing expense of carbon cartridges like with power filters.
Aerates and cleans water at the same time
Easy to remove and clean
Can use with any setup style
If biological filtration is desired (not just carbon) you will need some way to get your good bacteria colony growing.
You can use a bacteria supplement.
You can cycle your bowl first using liquid ammonia.
You can perform daily water changes and feed sparingly until it cycles.
Or you can throw in some floating live plants like hornwort to deal with the ammonia/nitrite until the filter is established.
This filter needs to be fully waterlogged to sink. Usually with time it will sink on its own and if you squeeze out all the air bubbles from the sponge. Worst case scenario you can always use a suction cup to hold it down by the airline tubing.
Maintaining this is very easy.
Just squeeze out the sponge once a week (or more frequently if possible) in old fish water.
If using carbon, that should be replaced weekly.
This filter DOES need an air pump and airline tubing to work.
Alternatively, the Aqueon Quietflow E puts out 25 gallons per hour and can be clipped or suction cupped (it is the lower priced of the two).
The nice thing is they can keep the water cleaner for longer, allowing more time between water changes AND helping to keep the fish small by not having to remove so much growth hormone.
You can also double up on your water cleaning abilities by growing live plants in addition to the power filter – supporting more fish.
Carbon inserts remove odor and toxins from fish waste and start working in hours, unlike beneficial bacteria colonies which can take time to develop in some situations
These kinds of filters do not allow you to grow a colony of beneficial bacteria in them unless you outfit them with some kind of a sponge instead.
Otherwise, the carbon cartridges are a continuing expense.
Some report chronic ammonia problems using carbon alone to control the fish waste, but it works well for many others.
These filters may create a stronger current that can stress the fish (depending on the size of the bowl you are using), so if that’s the case you can try putting a piece of sponge or cotton ball on the outflow.
Carbon cartridges should be changed weekly.
If using sponge inserts instead, these should be squeezed out in old fish water weekly
+5. The Planted Dirt Method
This is another fantastic method for creating a self-sustaining, balanced ecosystem to set up your bowl properly I have used (based on the Walstad method and modified for goldfish).
And it’s VERY low-tech.
Let’s get to it!
What you will need:
Small healthy goldfish
Live plants (a few recommended species are Bacopa Monteri (moneywort), Rotala Rotundifolia, pearl weed, Cabomba. Rooting, medium-fast growing plants are needed. Aerial plants such as dwarf water lettuce, duckweed and even water lily, lucky bamboo or pothos can be added to help out-compete algae for nutrients)
Small bag of organic potting mix (I used this kind)
Light source (indirect bright window light or LED light)
Fill the bottom of the bowl with 1″ organic potting mix. You may also use gravel or sand first around the edges to hide the dirt.
Cap the potting mix with 1/2″ gravel.
Plant your live plants so that about 50% of the surface is planted, then add the other 1/2″ gravel to the bottom misting occasionally to keep plants moist. Using tweezers to plant the stems makes things much easier.
Add decorations if desired and fill with dechlorinated water slowly. (Use a turkey baster to pour water onto a plastic lid with holes without disturbing the dirt.) If water is very cloudy from the soil, perform a 50% water change.
Add your small healthy fish. I like to start with baby goldfish and watch them grow, though very small babies 1/2″ and under are quite fragile and may not make it past quarantine after the stress of the pet store. Goldfish from trustworthy breeders are best.
Why this Method Works:
It’s so simple…
Live plants take care of oxygenating and purifying the water by absorbing ammonia and nitrite, eliminating the need for a filter or air stone. In turn, fish waste becomes plant food that encourages healthy plant growth. The dirt ensures superior plant growth.
Soil contains bacteria to immediately start breaking down fish waste and remove nitrite. It also stabilizes the pH and replenishes minerals, eliminating the need for water changes. Soil provides the plants with the nutrients and cO2 they need to thrive. Soil has 10,000 times the surface area of other substrates such as sand or gravel only. It promotes a strong colony of important probiotic bacteria that prevent disease.
No water changes keep the goldfish from growing large. Not heating the bowl prolongs their lifespan.
Round bowls rather than a drum fish bowl style will give you more surface area at the bottom, which will allow for more effective breakdown of fish waste by your plants and soil. For that reason I also tend to avoid tall, narrow vases the smaller the container, especially the more fish are desired. Increased surface area allows you to have more fish or feed heavier.
A lid is also a good idea, as it reduces the need to top up the evaporated water and prevents acrobatics that could lead to your fish drying up on the carpet.
Test the water each week to ensure the nitrate levels are within range (40ppm or under). If they are too high, consider performing a water change, adding more plants and reducing the amount of food.
You can substitute 1/2″ layer of sand for a cap rather than gravel, though the larger the goldfish the greater chance they will pop the cap.
Ammonia and nitrite might rise initially when freshly submerging soil when using other brands, so testing the water daily is a good idea. I have never experienced these issues with the Epsoma brand and get nitrates showing up in 2 days.
Sifting the potting mix first with a mesh strainer to remove the pearlite and sticks avoids prevents these floating up to the top.
Using a light will encourage superior plant growth, which will, in turn, provide more effective filtration in your bowl.
Before you set up your bowl this way, you can use it for a quarantine bowl for your new fish if you don’t already have fish in your bowl. Quarantine the fish separately before setting up your planted bowl. Treatments used for quarantine will harm or kill your plants and can affect the soil.
It can be low or no tech, depending on if you add an LED light or not. With a light, your plants will experience better growth.
No filter. No air stone. No air pump. No c02. No wait time for cycling. No new tank syndrome. Forget the demanding water change routine, the constant siphoning of waste from the bottom, the high cost.
Just let nature to do the majority of the work for you to enjoy a beautiful underwater world in your living space. It will also provide an interesting yet safe habitat for your pet.
Your responsibility? Once set up with healthy fish, all you do is… feed the fish daily or every other day and top off water every 1-2 weeks. That is it and that is all.
Working with dirt can be messy.
It takes more time initially to set up than some other methods.
Cautions & Tips
Please ensure the fish have enough oxygen. This is a must! Gulping at the surface (especially in the morning) or lethargy can indicate too much CO2 and not enough O2… as can overnight death. Many bowls have very little surface area for gas exchange. An airstone instantly fixes this problem. Too many live plants can cause O2 deprivation.
Please do not use too small of a fish bowl for the fish to swim around comfortably.
Please do not keep the goldfish in an empty bowl with nothing but water. This does not allow them to have any kind of natural stimulation. They like to forage and explore. Make their little kingdom interesting! Having “hides” is recommended.
Be sure they have access to foraging material to avoid boredom (read more about their diet needs here).
Please do not keep one goldfish all by itself. They are schooling fish by nature and enjoy having friends.
Take care not to overfeed. Only feed once a day or once every other day as much as they will eat in 30 seconds. Overfeeding can cause cloudy water, illness and fish death.
Be careful never to use any soaps or detergents other than unscented castile soap if cleaning the bowl.
Avoid placing the bowl in direct sunlight. This can cause overheating and even be a fire hazard as the glass can condense the light.
Tap the FAQ below to see the answer.
+Is it true that goldfish can't live in bowls?
Like many myths, there is an element of truth in this.
The typical goldfish bowl setup (a layer of gravel, water and a sculpture) DOES become unsuitable due to the lack of filtration. Without a filter or plants, ammonia and nitrite builds up to lethal levels. The oxygen level in the water drops dangerously.
But the bowl is not the problem – it’s the water inside it that’s become so deadly. Big tanks also can have the same ammonia/nitrite issues without a cycled filter or enough live plants to do the job.
Goldfish CAN live in bowls, but the bowl needs to be equipped to deal with the waste byproducts of the fish and allow for sufficient oxygen exchange. If you set them up right, your fish can live for many years in one happily.
(Note: people who say you can’t keep fish in bowls either haven’t ever done it themselves and are repeating online hearsay OR failed because they didn’t follow what I’m going to teach you below.)
+When should you NOT keep a goldfish in a bowl?
If your fish are already larger and matured, those fish will need more room to swim and should not be kept in bowls.
If you want your fish to grow large in the future, bowls are only suitable as a temporary setup with lots of large water changes.
+How many fish can I keep in a bowl?
However, there are no hard-fast rules (it all depends on your water quality and making sure the fish has enough swimming space). The situation can vary drastically depending on how large your fish start out, how much they grow, your water test results and how efficient your setup is.
I can only make some general recommendations.
Assuming your fish is still small, fingerling size and under:
A 2 gallon bowl could house 2-3 goldfish. A 3 gallon one could house 3-4. The larger the bowl the better if you want to keep a small group of fish.
Page recommends 1/2 gallon of water for every fish 3″ and under.
Personally, I like to use 1 gallon per goldfish as it gives them more swimming room.
Neither of these are “hard and fast” rules though.
It truly comes down to water quality and swimming space.
Please don’t keep your goldfish all by itself in solitary confinement – they are social creatures.
+Will my fish outgrow a bowl?
If you keep changing the water regularly, it is a very probable yes.
If you don’t want to keep upgrading to bigger and bigger aquaria, my advice is to focus on filtration – via plants or filters – to keep the water clean.
Changing the water and replacing it with clean water is what removes the fish’s growth inhibiting hormone that keeps them small.
+Will stunting hurt my fish?
There is no evidence that I have ever been able to find in all my years of study that points to stunting being harmful to goldfish.
The contrary seems to be true – stunted goldfish consistently live longer.
Slim-bodied fish like commons and comets are the most hardy and live the longest.
They are also the cheapest, though you will need to clean them up (more on that in the quarantine section).
Feeder fish have a low success rate due to being housed in such poor conditions and most infested with disease, though some report success with these.
But any kind goldfish around 5″ can be kept in a bowl if cared for properly.
+Isn’t gravel a choking hazard for goldfish?
For larger goldfish yes, but for small goldfish who can’t fit a piece of grave entirely in their mouth, no. Since we intend to keep the fish small this should not be an issue. However I encourage you to monitor the fish’s foraging habits to ensure the pebble is not getting picked up in their mouth.
+How Much/Often do I Feed the Fish?
Once daily or every other day is sufficient. It is VERY important not to overfeed.
Bowls can foul quickly due to the smaller water volume if overfed, so be aware of that risk and remember that it is better to underfeed slightly than feed too much.
30 seconds should be all it takes for the fish to finish the amount you provide in pellets, flakes or gel food. The rest of the day they should be allowed to graze on vegetable matter whenever they wish.
+When do I need to perform water changes?
It depends on how you set up your bowl.
Planted bowls can go without water changes for months at a time if balanced.
If you choose not to use live plants or a filter of any kind, it’s still possible…
…but you’re faced with the task of frequent water changes to keep the water in good shape.
More water changes also mean you are removing the growth inhibiting hormone.
This can cause the fish to outgrow the bowl.
When in doubt, go by your water test results.
If you ever have ammonia/nitrite, a large water change is in order.
Likewise, nitrate shouldn’t go above 40ppm.
+Do you have to have a filter?
If you’re referring to those electricity-driven ones, the answer is no…
… But only if you keep enough healthy live plants…
… OR if you change the water all the time.
Nature’s own filter is unparalleled.
A big mistake is when people use NO kind of filtration at all and don’t do those daily water changes, then that’s a recipe for disaster.
100% daily water changes keep ammonia at bay and the water safe for fish.
I have not personally used this method with success.
But there are some people who report that this works well for them.
So while I can’t personally endorse it, I’m putting it here for what it’s worth.
This method consists of lightly stocking and lightly feeding the fish with a weekly (or twice weekly) dump-out and gravel wash and no filter, and is perhaps seen as the standard care for goldfish bowls today.
(For what it’s worth, it seems most people who report success with this method are using well water.)
I will not say it can’t work.
But I will caution those who want to use this method that there are risks – and I have heard more negative than positive stories with its use.
Consequently, these are reasons people campaign against bowls:
Ammonia toxicity. No filtration, plants or otherwise, is taking care of the waste products excreted by the goldfish. This can result in elevated ammonia levels that culminate until the next cleaning. Black smudges are a classic indication.
Oxygen deprivation, since no aeration is being supplied. Evidenced by the fish gulping at the surface.
Outgrowing the bowl. Chronic water changes remove the growth inhibiting hormone and may cause some fish to quickly outgrow the container.
Why does it work for some and not others? It may be due to the fact that some goldfish are genetically hardy enough to deal with it.
Very sparing feeding and a larger bowl can also postpone accumulation of ammonia.
Tap the problem below to see the solution
+My fish is outgrowing its bowl
Likely there is too much water changing going on. If you change the water you remove the growth suppressing hormone goldfish naturally produce. If your system is balanced only water top-offs should be required for maintenance.
+My fish bowl has an algae problem
There are two secret weapons I use for this, the first is floating (aerial) plants which help block out excess light and are better at absorbing nutrients so algae is starved.
The second is the nerite snail, which is the best algae removing snail I have ever owned. They clean off the glass, leaves and objects in the tank like little janitors. They eat just about every kind of algae as well.
I always keep these snails in tanks or bowls I don’t want algae in.
+My plants came with little baby snails on them
Congratulations. These are harmless and help to break down debris, making it more bioavailable to your plants.
+I have ammonia and/or nitrite on my test results
It is common for some brands of freshly submerged soil to create ammonia and nitrite, monitor this for several weeks and perform water changes if needed. If you have chronic ammonia/nitrite problems after a month then there is too much waste for your plant load.
Consider adding more plants, faster growing plants, aerial plants, or a better light source for your plants and/or reducing the feeding. The plant Hornwort is a good nutrient hog.
If all else fails and you are just too overstocked you can always add a small filter in your bowl if desired, though in a balanced system this should not be necessary.
+The fish are gulping at the surface of the bowl
This can be caused by several factors, including:
Parasites affecting the gills
Low dissolved oxygen in the water
Parasites can be suspected if the fish were not from a trusted breeder and you did not quarantine them with proper treatments first.
For issues with low dissolved oxygen and/or ammonia/nitrite, adding more oxygenating plants such as ludwigia is usually just the ticket.
Too many plants can suck out oxygen overnight.
You can manually oxygenate the water by removing and pouring back in a cup of water.
Lastly, you can add an air stone to the bowl powered by an air pump, which is an instant fix that gives you peace of mind. Be sure you have a backup plan in case of a power outage, such as a battery powered air pump.
Low dissolved oxygen can indicate overstocking or not enough plants to deal with the bioload.
A dropping pH can happen if the alkalinity is not constantly replenished either by water changes, lime in shells, or soil.
+My fish always die shortly after getting them
The first suspect is the source of the fish. Low-quality sources or places that don’t quarantine (i.e. nearly all pet stores, fairs, etc.) have a high fatality rate.
After that, the next question is how you are taking care of them. Get a test kit and keep the ammonia and nitrite always 0, nitrate under 30, and the pH around 7.4 for the fish to thrive. Goldfish need some form of filtration (be it plants or a filter you buy) or water changes to keep their water good as they produce waste that will quickly foul it up if nothing is simultaneously removing it. Following the instructions on bowl setup will get you a long way ahead.
+My goldfish is eating the plants, what do I do?
If your plants grow fast enough this is not usually an issue, but if they are mowing down everything it is probably time to pick some tougher plants. I have never had an issue with Rotala Rotundifolia or Hornwort – though the goldfish do seem to snack some on the more tender plants such as anacharis and pearlweed (but it grows very fast).
The smaller the goldfish the smaller the chance they will be destructive to the plants. By getting a variety, you can help ensure some plants survive and eventually take over.
Got Pet Store/Fair Fish? Quarantine!
Not sure if your small fish are actually healthy?
Chances are they aren’t, unless you got them from a trusted breeder (or reputable importer).
They may look fine, but are probably carrying a load of “bugs.”
If you don’t deal with these to start with, they can end up killing your fish in about a month or so.
But don’t worry…
Your fish just need to be “cleaned up” at the beginning and then they will be good to go.
A quarantine bowl will need live plants (or filtration/water changes) to deal with their waste. Hornwort is my favorite as it floats and does not need to root. If it dies during treatments no big deal as I already have lots more where that came from.
For the quickest/simplest version of quarantine, you can use MinnFinn to treat all the most common goldfish diseases, followed by a salt treatment to get rid of ich parasites.