Do Fish Have Vertebrates: Are All Fish Vertebrates?

Some fish do have vertebrates in their anatomy, while others do not. A few different types of fish fall into this category- those with spinal cord, skull, and spine; those with cartilage between their bones; and those without any bone.

Vertebrates: A Review

Vertebrates are animals that have a spinal column – this is a structure made up of bones that runs down the center of their body.

All fish (except hagfish), amphibians, and reptiles have one! Even though vertebrates look pretty different, they all share some standard features: they possess a backbone (which is just hidden by their scales), fins for movement in water or on land, and the ability to move around using their spinal column.

Vertebrates can even swim using only their backbones! Spinal columns are an essential part of vertebrate anatomy as it allows them to move around and make changes in their environment. This makes them very versatile creatures and essential for survival.

Do All Fish Have Backbones?

No, not all fish have backbones. Some fish – such as hagfish, do not have bones in their skeleton. So, while all fish have some vertebrate characteristics, not all fish are considered to be vertebrates.

Fish Vertebrates Compared to Amphibians and Reptiles

Compared to amphibians and reptiles, fish has a more slender and flexible skeleton that is perfect for aquatic environments. Fish bones are also much lighter, making them easier to swim with. Amphibians and reptiles don’t have backbones as fish do – this is why they can’t move around as quickly in water since their fins won’t support them the way a backbone does.

All fish still possess vertebrate characteristics even though they lack spinal cord vertebrae; this includes amphibians and reptiles. The backbone is an essential skeletal feature for controlling movement in the water, just like on land.

What’s the Purpose of a Backbone?

Vertebrates are the primary type of animals that live in water habitats. Without a backbone, fish would not be able to swim or dive. However, backbones are essential because they allow fish to move forward and backward. All fish have some spinal cord level, but vertebrates have more complex brains and nervous systems than other fish. This is why vertebrates are sometimes called “backboned fish.”

How Do Bones Serve As Protection in Fish?

Backbones also serve as protection for fish. Bones are made of hard materials that help keep fish armored against predators, weather conditions, and other dangers in their environments. Additionally, fish use their bones to grasp and move something they want.

Which Fish Don’t Have a Backbone?

The only type of fish with no backbone is the hagfish, therefore, hagfish should not be confused with fish with a backbone (e.g., catfish, trout, and bass).


Hagfish is the only type of fish that doesn’t have a backbone- they’re just covered with scales! Hagfish live in the ocean and feed on small creatures that swim by. Additionally, hagfish can secrete a slime that can stick to things, making them hard to extract. The slime can also protect them from predators.

Fish Without Backbones

Some fish out there have a very flexible spine, allowing them to move around quickly and efficiently in their aquatic environment. Fish without backbones also tend to have a streamlined body, making them faster swimmers than those with backs.

Differences Between Fish Vertebrates and Invertebrates

The differences between fish without backbones and those with backs include the following:

  • Fish without a backbone have more minor scales on their body, making them look more like jellyfish.
  • Backboneless fish are typically faster swimmers than those with backbones, as they don’t have to use muscles for swimming; their streamlined bodies make them even faster!
  • Backboneless fish typically have a more flexible spine, which allows them to move around in different ways; for example, some can swim upside down or even backward!

How Do Backbones Grow

Backbones in vertebrates grow from cartilage, a flexible and robust tissue. Cartilage starts to form during embryonic development and grows until it becomes bone.

After becoming bone, cartilage shrinks back down and forms ligaments around the skeleton to support the body’s weight. Fish and other vertebrates are the only vertebrates that have backbones this way.

The Spine – What It Is and How It Works in Fishes

The spine is a long, thin piece of bone that runs from the head to the tail in most fish. The backbone supports the spinal cord and other vital organs in fish. Without a backbone, some backboneless fish (such as hagfish) would have difficulty moving around or staying afloat. Additionally, the spine can also be used to swim in different directions and upside down.

How the Spinal Cord Develops in Fishes

The spinal cord is a nerve cord that runs from the brain down to the tail in most fishes. In vertebrates, spinal cords grow until they become big enough to allow mammals and other animals to walk, swim, and even fly! However, backboneless Fish don’t have a spine, so their spinal cords are smaller than those of vertebrates.

What Makes Fishes Different From Other Vertebrates

Fish are vertebrates and, as such, share many standard features with other mammals. However, a few key differences set fish apart from other animals. For one thing, their skulls are entirely flexible – this makes them well-suited for diving and swimming underwater.

In addition to their skull flexibility, fish also have a spine-less spinal cord replaced by a series of nerve cords, allowing them to move their body differently and giving them an aquatic lifestyle.

Some of the main differences between fish and other vertebrates include:

  • Fish have a spinal cord that extends to their tails
  • Fish can move their heads and eyes around in different directions
  • Fish can breathe underwater
  • Some fishes can even swim backward