Pet fish and aquarium statistics (2026)
48 numbers about fish species, the people who keep fish, and the fish children most often keep, each with its source and year.
By Yechiel Kuperman, marine biologist. Last updated . Every number links to its source.
Key numbers
- There are about 37,799 valid species of fish. (Catalog of Fishes, 2026)
- 19,381 of those species live in fresh water, a little over half. (Catalog of Fishes, 2026)
- About 10 million US households keep freshwater fish. (APPA, 2025)
- 13% of UK households have an indoor fish tank. (UK Pet Food, 2026)
- 77% of US fish owners keep two or more fish. (APPA, 2025)
- Dissolved oxygen below 5 mg/L is stressful for fish. (US EPA, page read Oct 2026)
How many kinds of fish are there?
| Statistic | Number | Source |
|---|---|---|
| There are about 37,799 valid species of fish. | 37,799 | Catalog of Fishes, 2026 |
| 19,381 of those species live in fresh water, a little over half. | 19,381 | Catalog of Fishes, 2026 |
| Fish species are grouped into 5,353 valid genera. | 5,353 | Catalog of Fishes, 2026 |
| Scientists have published 62,939 species-level names for fish, many of them later found to be duplicates. | 62,939 | Catalog of Fishes, 2026 |
| 305 new fish species were described in 2026 up to late October. | 305 | Catalog of Fishes, 2026 |
| 409 new fish species were added in 2025. | 409 | Catalog of Fishes, 2026 |
How many American homes keep fish?
| Statistic | Number | Source |
|---|---|---|
| About 10 million US households keep freshwater fish. | 10 million | APPA, 2025 |
| About two million US households keep saltwater fish. | two million | APPA, 2025 |
| 77% of US fish owners keep two or more fish. | 77% | APPA, 2025 |
| Keeping a single fish has fallen 19% since 2018. | 19% | APPA, 2025 |
| 44% of US saltwater fish owners have a 56–125 gallon tank. | 44% | APPA, 2025 |
| Millennials make up 38% of US freshwater fish owners. | 38% | APPA, 2025 |
| 95 million US households own a pet of some kind. | 95 million | APPA, 2025 |
| Americans spent $158 billion on their pets in 2024. | $158 billion | APPA, 2024 |
How many UK homes keep a fish tank?
| Statistic | Number | Source |
|---|---|---|
| 13% of UK households have an indoor fish tank. | 13% | UK Pet Food, 2026 |
| 62% of UK households own a pet. | 62% | UK Pet Food, 2026 |
| The UK survey asks about 9,000 people each year. | 9,000 | UK Pet Food, 2026 |
How big do guppies get, and how many babies do they have?
| Statistic | Number | Source |
|---|---|---|
| Male guppies grow to at most about 5 cm (standard length). | 5.0 cm | FishBase, page read Oct 2026 |
| Female guppies are bigger, up to about 6 cm (standard length). | 6.0 cm | FishBase, page read Oct 2026 |
| A female guppy gives birth to about 20 to 40 live young at a time. | 20-40 | FishBase, page read Oct 2026 |
| FishBase gives a guppy pregnancy as four to six weeks (warmer water is faster). | four to six weeks | FishBase, page read Oct 2026 |
| FishBase lists a minimum aquarium length of 60 cm for guppies. | 60 cm | FishBase, page read Oct 2026 |
| Guppies do best at a pH of 7.0 to 8.0. | 7.0 - 8.0 | FishBase, page read Oct 2026 |
Pregnancy length depends on temperature: in a warm tank it is usually nearer three to four weeks. More in our guppy facts for kids.
How big do bettas get, and how long do they live?
| Statistic | Number | Source |
|---|---|---|
| A betta is on average 7.5 cm long. | 7.5 | Animal Diversity Web, page read Oct 2026 |
| The male betta guards the bubble nest until the eggs hatch, 24 to 48 hours later. | 24 to 48 hours | Animal Diversity Web, page read Oct 2026 |
| The average betta lifespan in captivity recorded by AnAge is 2 years. | 2 years | Animal Diversity Web, page read Oct 2026 |
| FishBase lists a maximum betta length of 6.5 cm (total length). | 6.5 cm | FishBase, page read Oct 2026 |
The two length figures differ because the sources measure differently: an average fish versus the largest recorded total length.
How big do goldfish get, and how long do they live?
| Statistic | Number | Source |
|---|---|---|
| Goldfish can grow to 15–45 cm long. | 15-45 | Animal Diversity Web, page read Oct 2026 |
| In captivity goldfish usually reach 2.5–15 cm. | 2.5-15 | Animal Diversity Web, page read Oct 2026 |
| The oldest reported goldfish age in FishBase is 41 years. | 41 years | FishBase, page read Oct 2026 |
| FishBase lists a minimum aquarium length of 100 cm for goldfish, which is why a bowl is a trap. | 100 cm | FishBase, page read Oct 2026 |
| A female goldfish usually spawns 2,000–4,000 eggs at a time. | 2000-4000 | Animal Diversity Web, page read Oct 2026 |
| Goldfish eggs hatch in 2–9 days. | 2-9 days | Animal Diversity Web, page read Oct 2026 |
| Goldfish become adults at 3–4 years old. | 3-4 years | Animal Diversity Web, page read Oct 2026 |
This is why a bowl is a trap for a goldfish. See the best first fish for a child.
How big do zebra danios get, and how long do they live?
| Statistic | Number | Source |
|---|---|---|
| Zebra danios average 25 mm long. | 25 mm | Animal Diversity Web, page read Oct 2026 |
| In captivity zebra danios live 42 months on average. | 42 months | Animal Diversity Web, page read Oct 2026 |
| Most zebra danio eggs hatch 48–72 hours after fertilisation. | 48 and 72 hours | Animal Diversity Web, page read Oct 2026 |
| In the wild, zebra danios cope with water from 6 °C in winter to 38 °C in summer. | 6 degrees | Animal Diversity Web, page read Oct 2026 |
How much oxygen do fish need?
| Statistic | Number | Source |
|---|---|---|
| Dissolved oxygen below 5 mg/L is stressful for fish. | 5mg/L | US EPA, page read Oct 2026 |
| Below 3 mg/L there is too little oxygen to support fish. | 3mg/L | US EPA, page read Oct 2026 |
| Water with less than 1 mg/L of oxygen is hypoxic and usually lifeless. | 1mg/L | US EPA, page read Oct 2026 |
How to raise it at home: how to add oxygen to a fish tank.
Are fish tanks safe for young children?
| Statistic | Number | Source |
|---|---|---|
| CDC advises that children under 5 should not clean or handle aquarium items. | 5 years | US CDC, page read Oct 2026 |
| If there is no soap and water after tank chores, CDC says to use hand sanitizer with at least 60% alcohol. | 60% | US CDC, page read Oct 2026 |
Which jobs a child can do: kids' fish tank setup checklist.
Where do aquarium fish come from?
| Statistic | Number | Source |
|---|---|---|
| Marine aquarium fish end up in more than two million homes and public aquariums worldwide. | two million | Rhyne et al., 2012 |
| In one year (2004–2005) the US imported more than 11 million marine aquarium fish. | 11 million | Rhyne et al., 2012 |
| Those imports covered more than 1,802 species from 125 families. | 1,802 | Rhyne et al., 2012 |
| Fish counts on US import declarations matched the invoices only 52% of the time. | 52% | Rhyne et al., 2012 |
| The marine aquarium trade targets at least 1,472 reef fish species. | 1,472 | Rhyne et al., 2012 |
For a first tank, choose fish bred in captivity, such as guppies, platies and zebra danios.
The same science, inside a funny story
George the Cranky Guppy is a chapter-book series for ages 7 to 10. The fish are characters; the biology is real.
See the booksSources
- Eschmeyer's Catalog of Fishes, California Academy of Sciences (2026). https://researcharchive.calacademy.org/research/ichthyology/catalog/SpeciesByFamily.asp
- APPA, 2025 Fish & Reptile Report (2025). https://americanpetproducts.org/news/from-bigger-tanks-to-stronger-bonds-fish-reptile-ownership-evolves-in-2025
- APPA, industry trends and stats (2024). https://www.americanpetproducts.org/industry-trends-and-stats
- UK Pet Food, survey methodology (2026). https://www.ukpetfood.org/information-centre/statistics/uk-pet-population.html
- FishBase, Poecilia reticulata summary (page read Oct 2026). https://www.fishbase.se/summary/Poecilia-reticulata.html
- Animal Diversity Web, Betta splendens (AnAge data) (page read Oct 2026). https://animaldiversity.org/accounts/Betta_splendens/
- FishBase, Betta splendens summary (page read Oct 2026). https://www.fishbase.se/summary/Betta-splendens.html
- Animal Diversity Web, Carassius auratus (page read Oct 2026). https://animaldiversity.org/accounts/Carassius_auratus/
- FishBase, Carassius auratus summary (page read Oct 2026). https://www.fishbase.se/summary/Carassius-auratus.html
- Animal Diversity Web, Danio rerio (page read Oct 2026). https://animaldiversity.org/accounts/Danio_rerio/
- US EPA, Indicators: Dissolved Oxygen (page read Oct 2026). https://www.epa.gov/national-aquatic-resource-surveys/indicators-dissolved-oxygen
- US CDC, Healthy Pets: Fish (page read Oct 2026). https://www.cdc.gov/healthy-pets/about/fish.html
- Rhyne et al., PLoS ONE 7(5): e35808 (2012). https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0035808