Ten Steps To a Healthy Goldfish


Fish1. A 20 gallon tank for one goldfish, and an additional 20 gallons for each additional goldfish. Mature goldfish average 6 to 8 inches in length and therefore need a big tank for just one fish. Goldfish also like to swim in a tank length wise, so I suggest getting a longer tank rather than a tall tank. For these reasons goldfish need a big tank for just one fish.

A filter

Fish 2.Reason: Goldfish are very dirty fish when they process thier food it goes through thier system fast since thier organs are squished into a tight space. Because goldfish create more waste than any other fish when they process their food, they require higher filtration levels than other types of aquarium fish. Filters for goldfish should be either the HOB (hang on the back) or the Canister and move at least ten times the water per hour as the size of the tank. For example, if you have a 10 gallon tank, you need a 100 gph filter. If you have a 20 gallon tank, you need a 200 gph filter, and so on.

Setting up the new tank

Fish 3. Goldfish love to pick up rocks so in my opinion you should have only an ich of sand or rocks. Just enough for them to forage during feeding time or live plants to survive. Sand or bare bottom is recommended over gravel since it's easier to keep clean and eliminates choking risk. Make sure when you get your rocks that you rinse them well with water to get rid of any debris. Then add your rocks carefully in to the tank. When adding the water to your tank add a Dechlorinator and place a flat dish in the bottom of the tank on top of your rocks so it doesnt splash the water so much. When done remove the dish.

New fish must be quarantined for a minimum of 4 weeks in a separate quarantine (qt) tank. It must be assumed that any new fish that has just come from the fish store is carrying some type of bacterial disease and/or parasite. If you introduce a new fish to your main tank without first quarantining the new fish, you risk passing on any disease or parasite to all of your existing fish in your main tank and the tank itself. Quarantines typically consist of a salt treatment and a several rounds of praziquantel as directed.

Lights and Heaters

Fish 4. Goldfish need light, just like you and I. You will also need a light if you choose to keep live plants in the tank. Heaters are not necessary in a goldfish tank. All goldfish can live in (water) temperatures from 78 degrees F to quite cold. Slim-bodied goldfish can tolerate low temperatures just below (above) freezing; however, (some?) fancy goldfish cannot tolerate water temperatures lower than around 55 degrees F. So, unless you want your tank at a constant temperature, goldfish don't need a heater. It is often more necessary to cool the water during the hot summer months. You can do this quite inexpensively by placing a small table fan so that it blows over the top of the water. There are also cooling fans made especially for aquariums.

Additives in the water

Fish 5. When setting up a tank or doing water changes you need to add some type of water detoxifier/conditioner to help get rid of the toxins in the water. Chlorine, chloramines and trace elements are present in all tap water. These things can be very harmful to your fish. Some water supplies also have other things in the water that are very harmful to fish. There are two basic groups of water detoxifiers/conditioners. Dechlorinators rid the water of chlorine, chloramines and trace elements. Some of these are NovAqua+ and StressCoat. Many of these also have an additive to protect and enhance the fishes' slime coat. The other group not only neutralizes chlorine, chloramines and trace elements, but also temporarily neutralizes ammonia as well. Some of these are Prime and Amquel. Both groups have their benefits. Allowing your water to sit for 24 hours will allow the chlorine to dissipate, but the chloramine and trace elements will remain, so it is important to use a detoxifier/conditioner.

Test Kits

Fish 6. The ammonia and nitrite levels are the first killers of most tanks, so it is very important to test your water daily while it is cycling and weekly once it has cycled. You need to have test kits for ammonia, nitrites and nitrates. You should also have a test kit for ph. Test kits for GH and KH can also be very helpful. Drop test kits are much more accurate and reliable than the test strips. You need to check the water before every water change. Also, if you are going to use a detoxifier/conditioner like Amquel or Prime, you will need a test kit that is "salicylate" based, because the "Nessler" based kit will give false readings when using these products.


Fish 7. You can use real plants if you like, but goldfish are nibblers, and although nibbling on plants is good for goldfish, your real plants won't live very long. There are some plants that goldfish don't really like to nibble on like Java ferns and the grass-like plants (the wider the leaves the better). If you don't want to spend a lot of money to maintain the looks of the tank, plastic or silk plants are better. Try to choose plants that are not sharp or pointy.

Decorations are fine to put in a tank, but, again, please make sure that there are no rough edges or sharp points. Decorations with hollow areas that fish can hide in are often not recommended as toxic gases can build up inside these hollow areas and can possibly make you fish sick.

Selecting Your Fish

Fish 8. Once your tank is cycled, you can start looking for a good and healthy goldfish.

What to look for:

a. Look at the tank the goldfish are in. Are there any dead ones in the tank? If there are, that normally means there is something wrong with the fish or tank and it is most likely that all of the goldfish in that tank will be sick.

b. Look at the fish you want. Is the fish you want aware of his/her surroundings? Is the fish actively moving around, is it looking around and very aware of things and nibbling at things or just staying in one spot? Goldfish that look more aware of what's going on are the better ones.

c. Look at the fish's eyes. The eyes should be clear and not foggy. If the eyes are foggy, the goldfish could have a disease or just blind.

d. Look at the fins. The fins should be erect. The fins should not be ragged. If the fins are always in the down position, or clamped, the fish could be sick.

e. Look at the fish over all. Make sure the fish doesn't have any signs of parasites (ick, anchor worm, etc.) or any type of disease (fungus, fin rot, etc.). These can generally be identified by white spots, white fuzzy patches, red spots or red streaks.

f. Once you have chosen your fish, make sure the pet store places the goldfish in a plastic bag, then in a brown paper bag, so the fish will not get stressed out by seeing what is going on around it. When you get the fish home to its tank, make sure you float the bag in the tank for 5 minutes so that the fish will get used to the temperature in your tank without stressing out the fish. After floating the bag in the tank for 5 minutes, open the bag and add some water from your tank into the bag and let the bag again float for about a minute. Try to not get any water from the fish bag into the tank as you dont know what is in that water. Then let the goldfish out, with either your hands, a net or a contanier and keep a close eye on the goldfish during the quarantine process to see if there are any problems with the goldfish.

Feeding Your Goldfish

Fish 9. There are many prepared foods out there for your goldfish and everyone has their favorites. Duckweed is one of the best kinds of foods you can give your goldfish. Its highly nutritious and helps to keep their digestive track going smooth. Make sure to choose foods that are high in protein and low in fillers. Goldfish also need to be fed a variety of fresh fruits and steamed vegetables for full, proper nutrition. Feed your fish at least once every day; what they can eat in 1-2 minutes or the food will spoil the tank.

Water Changes

Fish 10. Water changes should be done once a week. For goldfish, it is best to do a minimum of a 50% water change. To remove as many harmful bacteria from the tank as possible, it is also suggested that you do a 100% water change once a month. If you have a gravel substrate, you need to vacuum it very well to remove any uneaten food and waste that has collected in it. Rinse the filter, the filter media and decorations in tank water that has been removed from the tank. This will help preserve the beneficial bacteria that are living on them which make the water safe and healthy for the fish. Add clean water that has been treated with a detoxifier/conditioner.


Fish When you have your tank up and running you will need to understand the general rule of cycling the tank. You can cycle with or without fish. As fish can oftentimes die when you cycle with fish, it is best to do a fishless cycle. It is very important to have a tank that is cycled or the fish can get sick or die. Please read this link about cycling. Cycling a Tank


Written by: Lynda Von G and Shannon Wellman