How to set up a goldfish tank

As a child I believed that goldfish had a lifespan of a few months and lived in glass bowls. This was because we only ever won goldfish at summer fairs and we didn’t get a proper goldfish tank. As a result they rarely survived till the new school year.

It turns out the poor little things could potentially have lived for up to 50 years if we had only known the basics of caring for them.

I am sure there is a special corner of hell reserved for fish killers like me, So if you want to go to heaven and also keep goldfish for a long time, read and learn.

This time I wanted to do it properly so I bought a big(ish) new tank. The picture on the box showed me the fishy world that would soon be mine. I was (excuse the pun), hooked.

box picture

This particular goldfish tank doesn’t come with a heater. Unlike many other aquarium fish, goldfish do not need heated water, but they do need filters to clean the water they are in.

Gravel at the bottom of the tank should be rinsed before adding to the tank otherwise you end up with cloudy water that takes ages to clear. Don’t just use any old gravel. Use nice expensive and pretty ‘aquarium gravel’ that is low in calcium and has smoothed edges so as not to injure fish lips. I wonder who has the job of filing sharp edges off of gravel for fishes?


I thought the rocks were for my benefit but it turns out both the gravel substrate and the rocks are primarily there to provide a home for all the beneficial bacteria that will be busy munching on fish poo, uneaten food, and plant debris. Without the bacteria the ammonia and nitrates build rapidly and the poor fish don’t survive very long and then you have to stand in the corner and face the wall all afternoon .

Next, you want to think about plants. Goldfish are to be frank greedy little buggers who will eat almost any green items that they find. It’s for this reason that some tank owners put plastic plants in the goldfish tank. However that often looks shit a and besides, real organic greenery is an excellent dietary supplement that keeps your fish healthy.

So once you have added the gravel, and plants and water, you turn on the pump and for a few hours it all looks very good.

But then…

Oh the horror

Dont panic. The secret is to give the filter enough time to work its magic. This clouding is perfectly natural according to all the books and the wise words of Simon the fish shaman who works at Maidenhead Aquatics. Clearing the cloudiness will typically mean leaving your filter running with no fish in the tank for at least a week if not two or three. During that time natural bacteria build up in the water and all sorts of chemical changes occur. If you don’t do this then adding the fish to a fresh thank often leads to death of your fish in very short order.

Eventually visibility will begin to improve.

I mentioned that goldfish are greedy, but they are also hooligans. When they eat the plants they also tend to drag them around the tank too. It is not uncommon to find fishweed that was securely planted in the substrate the night before somewhere completely different come morning. Therefore, Ensure the weed is well planted at the bottom of the substrate and give it a good long time before introducing the fish so that the weed can send out some roots to anchor itself more firmly.


Many people add snails to their tanks in order to get cheap labour. Humans are terrible creatures. Nerite snails (Neritina spp.) on the other hand are brilliant. They are algae eaters who will take the green stuff off your glass walls and keep the tank looking lovely. Nerite snails also eat the fish poo that ends up on the bottom of the tank, but they don’t eat the plants. Three cheers for nerites. There are other aquarium snails but they either breed like rabbits or eat the plants so stick with a nice nerite and you wont go wrong.

Naming your goldfish

Very few website about goldfish offer naming advice. This is a mistake that Do It Properly can rectify.

It is too easy to name them on their first day at home, but we suggest waiting a few days to see their fishy personalities (fishionalities?) evolve before allowing inspiration to strike. Had we opted for the inital obvious choice of ‘Goldie’ we would never have discovered her actual name is “Myfanwy”.

(BTW: anybody older than 8 years of age who names a goldfish ‘Goldie’ should be taken to a Safari park and kicked out of the car in the ‘Savanah Enclosure’)

In fact here is a tip for nothing. Welsh girls names are excellent for goldfishes. Take a look at this list of named and you will wonder why there isn’t a law demanding that all goldfishes are named after Welsh women. You may disagree, but you would be wrong.

Update 2021

We are going to have to rename Maureen. Turns out she is a he. He has been chasing Myfanwy all over the tank and she has been producing lots of eggs. Although it may be tempting to try and raise the fry, we don’t have the space so we will just let nature take its course. I read that Goldfish are the UK’s third most popular pet and having had the tank for close to a year I definitely wouldn’t want to get rid of it.

Ongoing cost of keeping goldfish

The ongoing costs of keeping goldfish are pretty low. The electric for the pump and lights obviously cost a little and the food too. Then there is the ‘tap water conditioner’ added to every water change to dechlorinate the freshly added water. Other than that, the odd bunch of weed is about all you need.

If you have too little weed in the tank the fish may eat it all so you will need to regularly replace it. Start with too much and take out some until a self perpetuating balance is reached where the weed is growing at about the same rate that it is getting eaten. After that, you don’t even need to buy any more weed.

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About the author

Loves to learn new things and make stuff...properly. Born and living in the Thames Valley west of London, England. I have an office job during the day, but evenings and weekends are all about making.