Are sharks the only fish to have live young?

No, sharks are not the only fish to have live young.

While many fish lay eggs, there are several groups of fish that give birth to live young. These include:

* Sharks

* Rays (including stingrays)

* Skates

* Guppies

* Mollies

* Swordtails

* Platyfishes

* Sea Horses

* Seahorses

There are also several species of fish that can reproduce both through laying eggs and giving birth to live young, depending on environmental factors.

So, while sharks are well-known for their live births, they are not the only fish to do so.