Housing & Stocking Levels
Step 1: Finding an APPROPRIATE Home
Published July 13, 2015
One of the most important aspects to goldfish keeping is the living space you provide. When the proper housing and stocking levels are not met, a domino effect takes control leading to an unhealthy environment. Not giving your goldfish ample swimming room and over-crowding can result in excess waste, improper filtration, and rampant disease. Understanding stocking levels and how much space is required for a comfortable life is just the first lesson in goldfish keeping.
What are the recommended stocking levels?
Housing and stocking levels are dependent on the current size of the goldfish and their growth rate. In pristine conditions, fancy goldfish tend to grow the most in their first two years of life with a growth rate of about ranging from 0.25 - 1.5 inches per month. The main factors that determine their growth rate is the frequency and amount they are fed, and the water temperature. Goldfish fed a diet high in protein, they generally will grow faster than normal. In a heated aquarium they will reach their maximum size more quickly and could possibly grow beyond their max. But, the catch here is that a higher temperature leads to a shorter life expectancy. Regardless of what type of diet you're feeding and the water temperature, you should stock and house your goldfish with their maximum size in mind (fancy goldfish are generally 6” to 10” long). Don't worry too much about the diet and water temperature right now, we're going to get to that later.
Once people have one, they usually want more. Just remember that healthy goldfish lead to happy keepers, so don’t exceed the recommended stocking levels. During my research, I have learned two methods for stocking. The first has a minimum stocking level of 2.5 gallons (9.5 L) of swimmable space per 1” (2.5 cm) of body length. Swimmable space is the volume of water that is not taken up by substrate, decorations, plants, and internal equipment. The second, and more popular option, is a general recommendation of 15 - 20 gallons (56.9 - 75.7 L) of swimmable space for each double-tailed goldfish and 30 - 40 gallons (113.5 - 151.4 L) for single tails. The first method involving length as a limiting factor can be less accurate because goldfish have a tendency to be different shapes and sizes when fully grown. The second method is more often used because it already assumes maximum length and girth of a goldfish. As with everything, it is all about personal opinion. If you are providing 20 gallons/goldfish and it looks too tight, then it probably is. Sometimes rules needs to be broken to provide the fish with a healthy environment. Be honest with yourself and trust your decisions. If you feel like your fish would do better or have less stress in an "understocked" aquarium, go for it.
To determine the amount of gallons you need to house your goldies use the equations below:
First you want to determine the size of your tank (if you know how many gallons or liters your tank is, you can skip this step):
Volume (gal or L) = height X width X length (in or cm)
If you have an aquarium with decorations, plants, large rocks/driftwood, or internal equipment calculate the water displaced by these objects and subtract it from the total volume of the tank.
Using the first method, you want to determine the tank volume you need for ample swimming room. Make sure to consider the maximum length of the fish if you don't want to deal with upgrading the aquarium space later down the road.
Minimum Tank Size = Total Body Length X 2.5 gallons or 9.5 L
Using the second method, use the following calculation.
Minimum Tank Size = 15 - 20 gallons X Total Number of Goldfish
What type of housing should I provide?
The type of housing is less important than you might think. Goldfish can really be kept in anything, from the typical tank to a Sterilite container or even a lined apple crate. What I've found is most important when providing the five-walled container is it's shape in regards to length and height.
It is best to have a tank that is more shallow and long than deep and narrow. I’ve noticed that goldfish tend to swim vertically rather than horizontal. A higher depth of the tank can also cause problems with goldfish due to their predisposition swim bladder issues. Depth and pressure are proportionate, so when one increases so does the other. I’ll try not to bore you with the physics. Basically, the pressure in the tank is the weight of its volume divided by the area in which it sits. If the tank’s area is small and the depth is high, there is increased pressure at the bottom of the tank. The comfort level is around 6” to 18” depending on the size and shape of the goldfish. If you are looking for a container with a greater depth just make sure that the area the container sits on is large to displace the pressure. More rotund goldfish, like the Pearlscale, would do better with a lower depth while more streamlined goldfish, like the Comet, would be more accepting with a greater depth.
Where should I put my new aquarium?
Location, Location, LOCATION!!! I can not stress enough that the location of your tank can impact your goldfish. Placing an aquarium in high traffic areas can be very stressful for your fish and can lead to hiding when unknown people approach the tank. Large pets may be of concern too since they could damage or knock over a tank by jumping on it. Make sure to also share with children (and uninformed adults) that they should not tap on the glass. Goldfish do not have the traditional eardrums that we might think, instead they “feel” vibrations from sound. Water being an excellent sound carrier, tapping or even loud speakers can cause excessive vibrations that can startle and stress out your goldfish.
The placement of your aquarium in relation to your floor joist is extremely important, too. When placing your tank on a non-concrete floor, make sure that the tank is perpendicular to the floor joist. This allow for the full weight of the tank to be supported at multiple points. Keep in mind that the weight of one gallon of water is 8.35 pounds (or, 1L equals 1 kg). Multiple gallons of water, equipment, and decorations can be extremely heavy. In order for the floor to hold, the weight needs to be equally distributed over the joist. I don’t know about you, but coming home to find the tank crashed through the floor and possibly being in the living room of the downstairs neighbor is not an idea of fun.
I’m sure your fish will appreciate you following these recommendations for goldfish housing and stocking levels. Most of all, remember that we are Goldfish keepers Observing, Learning, and Developing Ideal Environments. Keep your eyes open, always be willing to learn from others and yourself to create a great atmosphere for your goldfish.
Happy Goldfish Keeping! - Nikita
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