Goldfish care

Aquarium size

"A general rule of thumb is 1 fancy per 10 gallons of water"

There are many “rules” to goldfish stocking ratios, like 20 gallons per fish, but these don’t take into account numerous physical and environmental factors that occur in our systems, such as water changes, regulated feeding, or filtration capacity, things which can really offset having a smaller aquarium.  In an ideal situation, a larger system is best for larger goldfish but smaller fish can cope perfectly well in tanks under a few hundred litres and, can then be upgraded further down the line. "But I thought goldfish only grow to the size of their tank?" In short... it’s a myth! Goldfish produce a growth-inhibiting hormone (GIH) that builds up in the water. When you do a water change, the hormone is removed and the fish continues to grow. A bigger tank helps to dilute this, which is why goldfish tend to get really big in larger systems. In a bowl or small tank, that hormone is very concentrated, unless lots of water changes are done all the time. Instead of getting obsessed about the tank size itself, its far more important for a goldfish to be provided with unpolluted water. If your tank is totally jam-packed with fish, it’s probably going to require daily maintenance. So larger, lower stocked setups can reduce maintenance. In setups with higher stocking densities, regular maintenance will be needed to keep water quality in check, however; you may encounter more aggression or breeding bahaviour, you’ll also have less room for error if the water quality starts to deteriorate.


"The more media the better, purchase a filter that holds as much media as possible"

Filtration is arguably the most important factor when keeping goldfish. Remember that your filter is purely a container to put your desired media in. Filtration is constructed of three main methods: Mechanical, Biological and Chemical which are all essential to running a fancy goldfish system. We use filters to reduce the need for water changes. Many of the original top view ranchu breeders in Japan relied solely on 100% water changes every day, whereas flow rate is possibly the least important factor when it comes to filtration. A flow rate of 5x tank volume per hour is ideal but if the size of the filter or flow rate is to be compromised, then I would always forgow the extra flow.

Mechanical - Removes physical waste from the water column. Large waste can be removed with coarse filter foams or Japanese matting, whereas fine waste can be removed with filter fleece. A range of mechanical media is beneficial before the biological section of the filter.

Biological - Should be the largest section within your filter. Your filter bacteria will survive on all physical surfaces within your aquarium so the more surface area, the more fish waste can be handled. Remember, media with small holes and high purosity can clog quickly and, media with low porosity will hold less bacteria. Our media of choice is Biohome mini ultimate!

Chemical - Filtration isn't used hugely for fancy goldfish. Chemical filtration, like carbon, can be used to remove hormones and pheramones from the water as well as checmial treatments.  Certain resins are used to remove nitrates, whereas zeolite can be used in new setups to remove ammonia and also trace levels of heavy metals.


"Good quality food not only improves growth and goldfish health but, also assists with water quality"

Feeding is a commonly debated topic on the Facebook group! Without it, we wouldn't be able to keep them! Good quality food is essential to growth, health and also can affect aquarium maintenance. There are three main types of food that are often given to fancies, these are pellets, gel and freshly prepared foods.

Pellet foods - can often be linked with swim bladder problems so it is good to buy the best quality pellet you can afford. A high protein level and low ash content are key to look for and a full fancy goldfish nutritional analysis requirement can be seen here.

Gel food is an alternative food preparation that you can use to supplement your goldfish’s diet or use as a more primary source of food. Gel food usually doesn’t contain any bulking agents or artificial additives, so it can be a good alternative to flakes or pellets. You can even make your own gel food at home with fresh fruit and vegetables. Click the link to the left to find out more.

Gel food is simple to prepare using a setting agent like gelatin or agar. You can include the protein-based ingredients that your goldfish love when making your own gel food, like pellets or mussels and prawns. You can also add extra items, such as red bell pepper, to help improve your goldfish’s colour, as well as spirulina, or other vegetables for additional fibre.

Fresh foods - It's easy to think that goldfish get all of their nutrition from pellets or flakes, but they need fiber that comes from fresh produce. Select a variety of ripe fruits and vegetables and clean them well. Then peel the produce. If they're soft, you can finely dice them and serve them to the goldfish. If the fruits and vegetables are firm, you'll need to finely chop them and heat until they're soft. Fresh foods can include but, aren't limited too: lettuce, spinach​, zucchini, carrots, cucumbers​, pepper and broccoli. To prepare it best, put your chopped veggies into a bowl of water and, microwave for a few minutes until soft. You can then chop them finely with a knife or food processor. Addionally, you could also freeze them into small cubes to be used as and when you need them.

Stocking your aquarium is dependant on numerous factors. This video provides a good summary!