Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsFish are commonly divided into three broad living groups: jawless fishes, cartilaginous fishes, and bony fishes. This is a useful introductory answer, not a complete count of every fish lineage or taxonomic rank.
The groups are distinguished mainly by whether they have jaws and by the predominant material in their skeletons. “How many groups?” is a different question from “How many fish species?”
What are the three main groups of fish?
| Group | Simple distinguishing feature | Examples |
|---|---|---|
| Jawless fishes | Lack jaws | Lampreys and hagfishes |
| Cartilaginous fishes | Skeletons are chiefly cartilage | Sharks, rays, skates, and chimaeras |
| Bony fishes | Characterized by a bony skeleton | The vast majority of present-day fishes |
These traits are a simplified guide for an introductory overview, not a complete diagnostic key. The Government of Western Australia’s Marine Waters resource describes the three main groups and their basic differences. OpenStax notes that bony fishes make up the vast majority of present-day fishes.
What are jawless fishes?
Jawless fishes lack jaws. The living jawless fishes include lampreys and hagfishes, which are separate kinds of fish within this broad group.
#1 Best Overall
- FIELD GUIDE TO FRESHWATER FISH
What are cartilaginous fishes?
Cartilaginous fishes, also called Chondrichthyes, include sharks, rays, skates, and chimaeras. Their skeletons are chiefly cartilage rather than bone, according to the Government of Western Australia’s educational resource.
What are bony fishes?
Bony fishes, or Osteichthyes, are characterized by a bony skeleton. They include the vast majority of present-day fishes. OpenStax gives an approximate figure of 30,000 bony-fish species; treat that as an attributed textbook estimate, not a current species census.
Are there more than three groups of fish?
Yes. Three is a broad introductory grouping; finer biological classifications recognize many more lineages and ranks. For example, a 2017 peer-reviewed phylogenetic classification recognized 72 orders and 79 suborders within bony fishes. Those are classification categories, not counts of fish species.
Some classifications further distinguish ray-finned and lobe-finned fishes within the broader bony-fish grouping. The number of “groups” therefore depends on the level of classification being discussed.
How many fish species are there?
The number of fish species is not the same as the number of broad groups. Species totals depend on the date and taxonomic source, and this article’s research did not establish a current authoritative total. Avoid treating historical counts as current figures.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Frequently Asked Questions
What are the three main groups of fish?
The usual broad introductory groups are jawless fishes, cartilaginous fishes, and bony fishes.
Are sharks bony fish?
No. Sharks are cartilaginous fishes; their skeletons are chiefly cartilage rather than bone.
Are lampreys and hagfishes jawless?
Yes. Both are living jawless fishes, though they are separate kinds of fish.
Outdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchWindows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallDoes “three groups” mean fish have only three subdivisions?
No. It is a broad overview. Finer classifications divide fish into many additional lineages and taxonomic ranks.
How many fish species are there?
That is a separate question from how many broad groups there are. Any species total should name its source and date; the research for this article did not establish a current authoritative total.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
