There are about 37,700 recognized living fish species in the world. Eschmeyer’s Catalog of Fishes lists 37,678 valid species in its July 7, 2026 update, while FishBase reports 36,535 in February 2026; the difference reflects changing taxonomy and database methods, not a contradiction about fish diversity.
The exact answer depends on what “types” means. This article uses “types” to mean scientifically recognized living species, not common names, synonyms, subspecies, fossil fish, or species that may exist but have not yet been formally described.
Key takeaways
- Scientists currently recognize about 37,700 living fish species worldwide; Eschmeyer’s Catalog of Fishes lists 37,678 valid species in its July 7, 2026 update.
- FishBase reports 36,535 fish species in its February 2026 statistics, showing why exact totals depend on the database and taxonomic decisions used.
- FishBase lists 17,672 freshwater species, 18,080 marine species, and 782 diadromous species in its habitat breakdown.
- The 62,807 species-level names in Eschmeyer’s Catalog are not 62,807 species because many names are synonyms or are not currently accepted as valid.
- Thousands of fish species may still be undescribed, but no precise worldwide total exists; NOAA Fisheries says there “may be as many as 20,000 more.”
What does “types of fish” mean?
In everyday language, “types of fish” might mean breeds, groups, common names, or species. For a scientifically meaningful answer, this article uses “types” to mean recognized living fish species. That excludes fossil fish, duplicate scientific names, subspecies counted separately, and species that may exist but have not yet been formally described.
The word “recognized” matters. A taxonomic database counts species that scientists currently accept as valid under its classification system. Researchers can later describe a new species, split one species into several, merge species judged to be the same, or move a species into another genus.
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How many species of fish are there in the world?
Scientists currently recognize roughly 37,700 living fish species in the world, although the exact number changes as taxonomists revise classifications and describe new species. The strongest current figure in this research is 37,678 valid species in Eschmeyer’s Catalog of Fishes, in its July 7, 2026 update.
That number is a dated scientific count, not a permanent total of every fish species that exists in nature. For a concise answer, “about 37,700 recognized living fish species worldwide” is more accurate than presenting 37,678 as an unchanging fact.
Why do fish databases report different totals?
Fish databases report different totals because they do not always incorporate taxonomic revisions at the same time or apply exactly the same treatment to names, synonyms, subspecies, uncertain records, and species boundaries.
| Source and date | Reported fish species | How to interpret the figure |
|---|---|---|
| Eschmeyer’s Catalog of Fishes, July 7, 2026 | 37,678 valid species | A current catalog count of species accepted as valid in the catalog |
| FishBase, February 2026 statistics | 36,535 species | A global fish information system’s current species total at that update |
| Eschmeyer’s Catalog, 2026 update | 408 new species described in 2025; 174 described during 2026 through the July 7 update | Evidence that the recognized total changes as new species are formally described |
The difference between 37,678 and 36,535 does not by itself show that either source is wrong. Eschmeyer’s Catalog describes its figure as the number of valid species recognized in current literature, while FishBase is a broader biodiversity information system covering fish taxonomy, biology, ecology, life history, and uses. Each source should be identified when an exact number is quoted.
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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsEschmeyer’s Catalog documentation says, “We feel the most current and most accurate counts of valid species is Eschmeyer’s Catalog of Fishes database.” That is the catalog’s own assessment of its taxonomic coverage, rather than proof that every database must produce the same total.
Are there really 62,807 types of fish?
No. Eschmeyer’s July 7, 2026 summary records 62,807 available names for use at the species level, along with 5,342 valid genera and 37,678 valid species. Available names are not the same thing as valid species.
The larger name total includes synonyms and other names that are not currently accepted as separate species. Older names can also be unplaced or otherwise unavailable under the catalog’s rules. Counting every species-level name would therefore count some fish more than once and would include names that do not represent a currently recognized species. The catalog’s species and genera documentation explains this distinction.
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Are there more freshwater fish or saltwater fish?
FishBase’s February 2026 habitat breakdown lists 18,080 marine species, 17,672 freshwater species, and 782 diadromous species, meaning fish that move between marine and freshwater environments. FishBase presents these as database categories, so they should not be treated as perfectly non-overlapping ecological boxes.
| FishBase category | Species reported in February 2026 | What the category means |
|---|---|---|
| Marine | 18,080 | Species recorded in marine environments |
| Freshwater | 17,672 | Species recorded in freshwater environments |
| Diadromous | 782 | Species that move between marine and freshwater environments |
Using the two principal habitat labels alone, FishBase reports slightly more marine species than freshwater species. The freshwater total is nevertheless remarkably large: freshwater habitats contain a major share of recognized fish diversity despite occupying much less area than the world’s oceans. FishBase’s number-of-fishes report provides the February 2026 breakdown.
How many fish species have been discovered?
About 37,700 living fish species have been formally recognized so far, with the exact total depending on the taxonomic database and update date. “Discovered” can be misleading because a fish may be observed or collected before scientists formally describe it and add it to a recognized species list.
The rate of change also includes more than brand-new field discoveries. Taxonomists may use genetic, anatomical, geographic, or ecological evidence to separate one species into several, or may determine that two previously named species are the same. A database total therefore reflects both biological discovery and ongoing classification work.
How many fish species are still undiscovered?
No one knows the precise number of fish species that remain undiscovered or scientifically undescribed. NOAA Fisheries states, “The most often quoted estimate of the number of fish species is 20,000,” and adds, “There may be as many as 20,000 more.” Those statements are a broad estimate, not a complete census of hidden diversity.
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A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Undescribed species are especially difficult to count in poorly sampled habitats, including deep water, remote reefs, caves, and some freshwater systems. The possible additional species should not simply be added to 37,678 to produce a final measured total. The careful conclusion is that thousands of additional fish species may remain to be documented, but the worldwide number is uncertain. NOAA Fisheries gives the estimate in its official fish facts resource.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What is the most accurate number of fish species?
For a single current figure, use 37,678 valid living fish species and name Eschmeyer’s Catalog of Fishes and its July 7, 2026 update. For general readers, the safest rounded wording is: “Scientists currently recognize roughly 37,700 living fish species worldwide, although the exact number changes as taxonomists revise classifications and describe new species.”
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FishBase’s nearby figure of 36,535 is also useful and should not be discarded simply because it differs. Exact counts become outdated as databases add descriptions and taxonomic revisions, so figures should be rechecked before republication; the research behind these figures was checked on August 13, 2026.
How can you learn to identify fish?
No single printed book can cover every one of the roughly 37,700 recognized fish species. Readers who want to identify fish they see should choose a guide for a particular region or habitat, while readers studying classification may prefer a broader fish-diversity reference.
A broad fish diversity guide, Fishes: A Guide to Their Diversity, is described as a classification and morphology reference for students, scientists, and naturalists. A regional fish field guide is often more practical for identification: Johns Hopkins University Press lists A Field Guide to Coastal Fishes: From Maine to Texas, Second Edition, covering more than 1,140 species from that region, with publication scheduled for January 12, 2027. Neither book should be treated as a complete guide to all fish species worldwide.
Frequently Asked Questions
How many species of fish are there in the world?
Scientists currently recognize about 37,700 living fish species worldwide. Eschmeyer’s Catalog of Fishes lists 37,678 valid species in its July 7, 2026 update, while FishBase reports 36,535 in its February 2026 statistics.
Are there more freshwater fish or saltwater fish?
FishBase reports 17,672 freshwater species and 18,080 marine species in its February 2026 habitat breakdown, plus 782 diadromous species that move between marine and freshwater environments. The categories are database classifications and are not perfectly non-overlapping ecological boxes.
How many fish species are still undiscovered?
No precise worldwide count exists for undiscovered fish species. NOAA Fisheries says there may be as many as 20,000 more, but that figure is a broad estimate and should not be added to the recognized total as though it were a measured census.
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What is the most accurate number of fish species?
The most accurate single current figure in this research is 37,678 valid fish species in Eschmeyer’s Catalog of Fishes, updated July 7, 2026. A rounded figure of about 37,700 is safer for general writing because species counts change continuously.
The Bottom Line
Bottom line: The best current answer to “How many types of fish are there in the world?” is about 37,700 recognized living species. Eschmeyer’s Catalog lists 37,678 valid species as of July 7, 2026, while FishBase lists 36,535 in its February 2026 statistics. The totals differ because fish taxonomy changes and databases apply classifications at different times; thousands more species may remain undescribed.
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