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Understanding how often to feed goldfish is an important concept for all owners to understand. In learning how often to feed fish of any species, it comes down to one critical point: temperature.
Why is temperature important in feeding fish?
Almost all fish, with very few exceptions, are ectotherms. This means that their body temperature is regulated by their external environment. They have no control over how warm their core temperature is, unlike humans, cats, dogs and many other pets. A fish’s body temperature dictates its metabolism, reproduction, growth and immune function. The warmer it is, the faster these mechanisms work. Too hot, however, a fish’s body will reverse the process, just like a human that overheats.
Goldfish are temperate fish, unlike most of the tropical fish in the pet industry. They thrive in water temperatures in the mid to high 70s (20s C). The warmer their tank, the hungrier they will be and the more frequently you will need to feed them. Most goldfish tanks are best when kept at room temperature, WITHOUT a heater. Goldfish should NOT be kept with tropical fish since the warmer water temps, required for tropical species, will keep their metabolisms burning constantly.
Outdoor goldfish can tolerate a wide variation in temperatures, but their metabolism will vary significantly more. It is critical that you have a good thermometer on your pond in order to determine how much to feed your fish.
How often do wild goldfish eat?
In the wild, goldfish’s ancient cousins, carp, forage all day long. This behavior is commonly seen in pet goldfish, where they root around their substrate all day long, looking for lost tidbits. You may see your fish pick up some small pieces of rock or gravel and spit them back out. Do not be worried that these pieces may get stuck. We have had only ONE case in our long history of a pebble getting stuck and it was due to a rare oral deformity. Learn more about what to do if you suspect your fish may have a pebble stuck in its mouth.
How often to feed goldfish?
Again, this comes down to temperature. If you are unsure what the water temperature is, invest in a reliable thermometer. Once you know what your tank or pond temperature is, you can follow the chart below. Keep in mind, this chart is just a rough outline. Your fish’s individual metabolism may not follow these guidelines exactly.
|Below 50-55F (10C)||Very infrequently (once a week) to none|
|50-60F (10-15C)||Once to twice a week|
|60-70F (15-21C)||Every other day or once a day|
|70-75F (21-24C)||Once a day to twice a day|
|75-80F (24-27C)||Twice a day|
|Above 80F (27C)||Twice to three times a day|
What should I feed my goldfish?
There are many commercial foods available for goldfish. We recommend a pelleted diet around 32-35% protein and 7-8% fat. Here is more information on proper goldfish diets and our favorite goldfish diet to recommend to clients.
I am going on vacation. How long can my goldfish go without food?
Again, it all comes down to temperature, but don’t try to cheat and manipulate your water temperature super quickly! This can seriously stress out goldfish and cause lots of issues if they are not ready for a quick cool down. Here is a good reference for how long your goldfish can go without food.
If you are not home to take care of your goldfish. There are a few points to consider.
- If you are having someone fishsit for you, measure out the daily rations in individual baggies and HIDE THE BAG! Too many disasters happen when owners are away and caretakers “feel sorry” for your fish.
- If you must use a vacation feeder, use this one. It allows for proper diet management. DO NOT use those awful “vacation feeder” bricks! They are terrible for your fish and your water quality.
- Do your routine maintenance right before you leave. Remember, water quality is key to happy and healthy fish!
Learn more about proper vacation care for fish here.