The Ultimate Goldfish Bowl Guide

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.

The goal?

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.)

Let’s get started!

You’ll Need:

• Fish Bowl
• Sand
• Plants
• Shells/pebbles
• Dechlorinator
• Healthy young goldfish
• Ideally some scavenger snails (often come with plants)

Instructions:

1. Place roughly 1/2″ sand layer on the bottom of the bowl (more can be used if growing rooting plants).
2. Add a few shells (and pebbles, if desired) to the bottom.
3. Add any other desired decorations.
4. Slowly add 2″ of dechlorinated water and add plants (see recommend types below). Fill the rest with water.
5. 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

Tips:

• 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 (I got mine here) and duckweed (find it here).
• 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 (see here).
• 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.

Maintenance

This style of a 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.

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.

What You Will Need:

• Fish bowl
• Undergravel filter (with air pump & airline tubing)
• Pea gravel
• Small, healthy goldfish
• Water conditioner & fish food

Instructions:

1. Assemble the filter according to package instructions and place the bowl filter plate at the bottom of the empty bowl.
2. Fill the bowl with 1/2″ gravel (even better would be Seachem Matrix).
3. Optional: add a clump of hornwort (really helps go longer between cleanings). Place any other decorations if desired and fill with dechlorinated water.
4. Connect the airline tubing to your air pump and turn on.
5. 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.

Tips:

• 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.

Pros:

• 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.

Cons:

• 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

Maintenance

Cleaning is usually required every 7-14 days.

This involves the following:

1. 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.
2. 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.
3. 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).
4. 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).
5. 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.
6. Change the charcoal in the filter for fresh (it doesn’t usually last more than a week or so).
7. 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).

Sponge filters offer fantastic surface area for good bacteria to grow.

It does a fantastic job of aerating the water too!

And the current?

Soooo gentle (perfect for goldfish!).

What You Will Need:

• Fish bowl
• Sponge filter
• Air pump & airline tubing
• Small healthy goldfish

Instructions:

1. You can use ANY style of fish bowl substrate or decor with this filter. Sand, gravel, plants, marbles… up to you.
2. 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).
3. 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

Pros:

• 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
• Simple setup

Cons:

Now:

If biological filtration is desired (not just carbon) you will need some way to get your good bacteria colony growing.

1. You can use a bacteria supplement.
2. You can cycle your bowl first using liquid ammonia.
3. You can perform daily water changes and feed sparingly until it cycles.
4. Or you can throw in some floating live plants like hornwort to deal with the ammonia/nitrite until the filter is established.

Note:

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.

Maintenance:

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.

These kinds of filters come with small aquarium kits such as the hugely popular Tetra LED 3 gallon cube aquarium.

They can also be purchased separately.

The Tetra Whisper 3i (the filter in the kit above) pumps out 20 gallons per hour.

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).

Pros:

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

Cons:

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.

Maintenance:

Carbon cartridges should be changed weekly.

If using sponge inserts instead, these should be squeezed out in old fish water weekly.

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:

• Fish bowl
• 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)
• Pea Gravel
• Light source (indirect bright window light or LED light)

Instructions:

1. 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.
2. Cap the potting mix with 1/2″ gravel.
3. 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.
4. 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.
5. 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 keeps the goldfish from growing large. Not heating the bowl prolongs their lifespan.

Tips:

• 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.

Pros:

• 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.

Cons:

• Working with dirt can be messy.
• It takes a more time initially to set up than some other methods.