How long do fish live...?

Fish lifespans vary dramatically by species, environment, and care.

Some fish live only a few months, while others can survive for centuries.

Here’s a detailed breakdown:

Typical Fish Lifespans by Type

• Small freshwater fish (e.g., guppies, tetras)

1–5 years

Popular aquarium fish; lifespan depends on water quality and diet.

• Goldfish / Koi

10–30 years (common), 40+ years (well cared for)

Fancy goldfish ~10–15 years; Koi can reach 50+ years; record koi “Hanako” lived 226 years.

• Angelfish / Cichlids

10–20 years

In aquariums; larger cichlids may reach 25 years.

• Betta / Siamese Fighting Fish

2–5 years

Short-lived unless very carefully maintained.

• Salmon / Trout

3–8 years

Many die after spawning (semelparous species).

• Tuna

15–50 years

Some large species (e.g., bluefin tuna) can live decades.

• Sharks (various species)

20–500+ years

- Great white ~70 years- Greenland shark estimated 272+ years (oldest vertebrate)

• Deep-sea fish

50–200+ years

Cold, low-predator environments allow extreme longevity.

• Ocean Quahog / Clams

100–500+ years

Bivalves like Ming the clam reached 507 years.

• Sturgeon

50–100+ years

Large freshwater species, slow-growing; some 150+ years.

Factors Affecting Fish Lifespan

Species & Genetics: Some fish are naturally short-lived (e.g., guppies), while others grow slowly and live longer (e.g., sturgeon, sharks).

Environment: Cold-water species with fewer predators live longer; aquarium fish often live shorter lives without ideal care.

Diet & Care: Proper nutrition, clean water, and stress-free habitats significantly extend lifespan.

Size: Larger fish generally live longer; e.g., small goldfish vs. large koi or sturgeon.

Reproduction Strategy: Semelparous fish (like salmon) die after spawning; iteroparous fish reproduce multiple times and live longer.

Are UK fish populations declining?

There isn’t a single simple number for how many fish species there are in decline in the UK, because scientists usually track fish stocks (populations) rather than counting individual species in a yes/no way.

But the latest research gives a clear picture:

Key figures (UK fish)

Around 105 fish stocks are assessed in UK waters. (� envirolink.org)

17 of those are in a critical state (both overfished and overexploited). (� envirolink.org)

About 1 in 6 stocks (~17%) are critically depleted and still being overfished. (� Oceana UK)

Only ~41% of UK fish stocks are considered healthy, meaning the majority are not. (� Phys.org)

What that means in plain terms

A significant share of UK fish populations are declining or in poor condition. At least dozens of fish populations (stocks) are already in serious decline. Many more are under pressure or not sustainably managed, even if not yet collapsed.

Important nuance

“Fish species in decline” is harder to pin down because:

A single species (like cod or herring) can have multiple regional stocks, some worse than others.

Reports therefore focus on stocks (populations) rather than species counts.

Roughly tens of UK fish populations (at least ~17) are in serious decline, and well over half are not in a healthy state overall.

Notable points

The Greenland shark is by far the oldest known fish, with one individual estimated at nearly 400 years old, meaning it may have been born before the early 1600s.

Many of the oldest fish are deep-sea species, where cold water and slow metabolism contribute to exceptional longevity.

Ages are commonly determined by examining otoliths (ear stones), vertebrae, or other tissues. The Greenland shark is a special case because researchers used radiocarbon dating of proteins in the eye lens.

Oldest documented fish

Here are some of the most famous verified or historically documented individual fish known for exceptional age (Fish/Species/Age/Status)

Hanako: Koi

Age: 226 years (claimed)

Famous Japanese koi. The age claim is widely repeated but remains disputed because it was based on scale analysis and lacks strong peer-reviewed verification.

Granddad: Australian lungfish

Age: 109 ± 6 years

Oldest aquarium fish whose age has been scientifically estimated using DNA methods. Guinness World Records recognises this record.

Methuselah: Australian lungfish

Age: 93 ± 9 years (living)

Currently regarded as the oldest living aquarium fish, residing at the Steinhart Aquarium.

Unnamed female: Bigmouth buffalo

Age: 112 years

Oldest age-validated freshwater fish, confirmed by otolith analysis and radiocarbon dating.

Unnamed Greenland shark: Greenland shark

Age: ~392 years (estimated)

Oldest individual fish ever scientifically estimated, using radiocarbon dating of eye-lens tissue. The exact individual was never given a name.

Which record is considered the oldest?

Oldest scientifically estimated fish is the unnamed Greenland shark, approximately 392 years old.

Oldest named fish is Hanako at 226 years, though this record is controversial.

Oldest verified aquarium fish is Granddad, 109 years.

Oldest living aquarium fish today: Methuselah, estimated at 93 ± 9 years.

The remarkable ages of these fish are often linked to extremely slow growth and metabolism, particularly in cold-water species like the Greenland shark, which may not even reach sexual maturity until around 150 years of age.

Learn more about:

How to build a newt-friendly pond

Protecting amphibians in urban environments

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