Buying or adopting a pet is nearly the same thing as entering a long-term relationship. Every pet owner anticipates year after year of companionship, appreciation, and caretaking. Fish keepers are no different than the owners of cats and dogs in this regard. Whether peering through the glass at a pet store, or browsing the internet and looking at photos of different aquatic species, we all imagine the daily routine of feeding and tank care. These tasks allow us to appreciate each day we have with our pets.
Fish are unique, however, in that their lifespans can vary widely from species to species. The average fish lifespan is 5 years. Tank care also plays a role in the longevity of your pet. These factors include water parameters, diet, parasites and bacteria, and even tank mates. However, by managing all of these details in their aquariums, owners can add years to the lifespan of their fish, many of which can live for 15-20 years.
Lifespans of 21 Popular Fish
Goldfish
The goldfish, surprisingly, can have one of the longest lifespans of any captive fish. If well cared-for, this hardy fish will live at least 10 years, and may survive up to 30.
Swordtail
This common aquarium fish has an average lifespan of roughly 5 years, which is short in comparison to other species. The swordtail is a live-bearer, and shorter lifespans are typical of these types of fish.
Guppy
The freshwater guppy is another live-bearing fish, with a maximum lifespan of 5 years. More commonly, they live between 1-3 years in home aquariums.
Tetras are hardy and adaptable, which makes them an excellent beginner fish. Their lifespan is between 5 and 10 years.
Betta fish are popular for several reasons, including their graceful shapes, vivid colors, and adaptability. A lifespan of 2 years is commonly cited, but many owners report bettas living up to 5 years.
This semi-aggressive saltwater fish is a pricy, but much sought-after species, thanks in part to its striking appearance. With good care, many individuals will live at least 15 years, and some up to 20.
This freshwater fish bears no relation to the family of saltwater angels, but are notable for their appearance and personalities. They will commonly live upwards of 10 years.
Clownfish
The popularity of the clownfish is as much derived from their looks and temperament as their association with a starring role in a certain Pixar film. This saltwater species has a common lifespan of 5 years in home aquariums.
Tangs
Tangs can be found in numerous colorations and body shapes. At least 80 distinct species exist in this salt water family. With a lifespan that can exceed 25 years, they are one of the most long-lived aquarium fish.
The Jack Dempsey earned its name from the famed boxer, but is as recognizable for its dynamic color pattern. It will live for 5-7 years if well-cared for.
Corydoras (Catfish)
These freshwater fish are bottom dwellers, and well-liked for both the peaceful personalities and utility as algae eaters. They will often live for 5 years, but can live for much longer, depending on the individual and tank conditions.
Wrasses
Like many of the fish on this list, wrasses include a variety of species. They are a healthy saltwater fish, but not as long-lived as other types. Some individuals may live past 5 years, but owners should expect a 3-4 year lifespan.
Small but distinctive in appearance, these Rasboras are favored by freshwater tank owners for their health and temperament. 5 to 8 years is their expected lifespan.
Oscar
Oscars belong to the cichlid family, a freshwater group that also includes angelfish. Average longevity for these carnivores is between 10 and 12 years, with some living as long as 20.
Platies
Platies are small, colorful freshwater fish, which give birth to live young. As with many livebearers, they have a shorter lifespan, about 3-4 years.
Lionfish
Lionfish are recognizable even by non-enthusiasts for their array of fins that fan out around their body like a mane. Given proper care, these saltwater species may live over 16 years.
Damsels
This saltwater fish is vibrantly colored, and has a peaceful personality. In captivity, they can live for up to 20 years, though a range of 10-12 years is more common.
The largely herbivorous clown loach is a bottom feeder, and even has small whiskers, similar to some catfish varieties. They are also long-lived, often exceeding 20 years in age.
The green chromis is among the most common saltwater species. They have a social temperament to accompany their bright colors.
Butterfly fish
These saltwater fish are brightly colored, and include at least 114 species. In captivity, they will generally live to around 7 years of age.
Mollies
Mollies are a unique fish, namely for the ability to live in both freshwater and saltwater, provided owners allow them to acclimate to their conditions. They will live up to five years, but some owners report that shorter lifespans when they are kept in saltwater.
What Factors Affect Fish Lifespans?
The lifespan of aquarium fish is dependent on a number of variables. Some of these factors may be common sense, while others are not as intuitive.
Tank Size
First, and perhaps most simple of all, is ensuring that a fish tank is the proper size for the fish. Basic aquarium guidelines recommend one gallon of tank space per every inch of fish life. This is only a starting point, however, and most fish will benefit from additional swimming space.
Water Parameters
Foremost is maintaining proper water quality. The wrong parameters may allow parasites and bacteria to develop within the tank, and these often prove difficult to get rid of. It may also lead to a buildup of algae and detritus, which fouls the water and causes imbalances in oxygen levels.
Check the water hardness and pH on a regular basis, use the proper filter for the size and type of fish tank, and keep a thermometer in the water to monitor and adjust the temperature. The equipment for these measurements should always be kept on hand.
Diet
Diet is another key factor in the lifespan of aquarium dwellers. Most fish species have evolved in specific habitats, and are accustomed to eating what is available in those regions. Know whether they are carnivorous, omnivorous, or herbivorous, how often and how much they need to be fed, and what macronutrients are important for them.
Tankmates
Tankmates can also affect the longevity of aquarium fish. Fish of similar temperament should be kept together to minimize stress and reduce the risk of predation by larger or more aggressive fish. This can also minimize stress, and allow for optimal levels of feeding and swimming.
Maximizing the Lifespan of Aquarium Fish
Once you’ve purchased a tank large enough to accommodate your fish, your first priority should be finding the correct filter for both the water volume in your tank, and the amount of flow preferred by your species. This allows tank owners to not only keep their tank as clean as possible, but to replicate the water flow rate their species would experience in its natural habitat.
In addition to proper filtration, owners may find it helpful to purchase a heater for their tank. Air temperature can fluctuate depending on both the time of day and season of year. A consistent water temperature reduces the physical stress on fish to constantly adapt to hotter and colder water.
Source of Fish
Try to ensure that new fish are sourced from breeders that closely monitor health and water quality as well. Often, the short lifespans reported by some aquarium owners result from pre-existing conditions, such as bacteria or parasites, that the fish may have acquired from the tank they were raised in. If the fish are roughly handled during their transition from tank to tank, that will compromise their immune system.
Tank Maintenance
Aquariums should also be cleaned regularly to remove excess food, algae, and to refresh and replace the water. Water will naturally degrade in quality due to waste from inside the tank, and contaminants from outside of the tank. Cycle your water either monthly or bi-weekly for best results.
Learn About Your Fish
An understanding of each individual species in an aquarium is crucial. This not only allows owners to provide the correct diet and water parameters, but to also quickly spot changes in behavior or appearance. If a fish seems less active, less enthusiastic about feeding, or shows any abnormalities in appearance, that can be an indicator of an infection. Fortunately, many antibiotic and parasite treatments can simply be added to the tank water, and have a high rate of effectiveness if used early enough.
Fish Lifespans: Fun Facts
Greenland Shark
At over 28,000 species, fish make up nearly half of all invertebrate life on the planet. In fact, the oldest vertebrate in the world is the Greenland shark, a fish that takes an entire century just to reach adulthood.
Koi fish are also famed for their longevity. Numerous individuals from Japan and around the world have been reported to live for over 200 years. These exceptional animals are generally kept within a family, and cared for by multiple generations.
Goldfish
Goldfish, which are closely related to koi, can also be very long-lived. Tish, a goldfish won at a fair by a family in the United Kingdom, lived to be 43 years old. Goldie, also won at a fair in the UK, lived to 45, the oldest recorded lifespan of any goldfish.
Buttkiss the Black Pacu
In the United States, a black Pacu named Buttkiss, has had a lifespan of at least 43 years, much of which he has spent in an aquarium store in Queens, New York.
Blue Hippo Tang
The Blue Hippo Tang, a saltwater species that served as inspiration for the character of Dorie in Finding Nemo, is also one of the longest lived aquarium tangs. It can reach 20 years of age in home aquariums.
Conclusion
A home aquarist may consider such elements as appearance, temperament and diet when choosing a fish. Lifespan is just as important a consideration, as many fish can be as long-lived as a cat or dog. Owners who are attentive to the finer details of their tank will be rewarded with years of enjoyment from their aquatic companions.
