Back-to-Schooling September: Questions from Guests!

September 18, 2025

Thank you for submitting your curiosity questions during Back-to-Schooling September. Here are answers to some of the questions that we did not yet answer on social media.

How do sharks sleep?
Sharks do not sleep like humans do, but they do have restful and active periods. Because many sharks must swim constantly to breathe, they only rest half of their brain at a time; the other half stays awake to maintain basic functions like swimming. They also don’t have eyelids to close, so their eyes stay open while resting.

Do fish fart?
Fish can release gas for a variety of reasons, but it’s not usually due to digestion. Many fish have swim bladders to control their buoyancy in the water; they release gas to adjust their position in the water. Some fish release gas to communicate to one another in schools. Fish that lack swim bladders, like sharks, typically do not fart.

How many tentacles do jellyfish have?
Jellies (they’re invertebrates, not fish) have a wide range of species and therefore a wide range of tentacles. Moon jellies, like you can see at the Aquarium, typically have 8 tentacles with stinging cells for trapping food and 4 frilly oral arms that help clean the body and direct food to the mouth. Other species like lion’s mane jellies can have hundreds of tentacles, and the tentacles on a Portuguese man o’ war jelly can be more than 30 feet long!

Will you get a hammerhead shark?
A top priority of the Aquarium is animal wellbeing. Habitats at the Aquarium must provide the needs of animals to not only survive but thrive. Hammerhead sharks have needs that cannot be met well in an Aquarium setting. Their large size (13 feet long) and constant movement would require a huge open space, larger than the Aquarium can accommodate in a historic building. Hammerheads are also highly sensitive to changes in water quality, light and noise, which could cause significant stress in an Aquarium setting. And, hammerhead sharks are a highly social species, spending time in large schools. In order to properly care for a hammerhead, you’d need a whole group of other hammerheads too.

Why is the water for the stingrays deep?
The stingrays in the touchpool have choice and control over their environment. If they are curious and want to come to the surface within touching range, they can. If they want a break or a rest, they can swim deeper in the water to avoid interaction. The deeper pool helps ensure healthy stingray wellbeing.

What is the difference between a whale and a whale shark?
Whales are mammals. They have hair, are warm-blooded and produce milk to feed their young. Whale sharks are fish. They are covered in dermal denticle scales, are cold-blooded and their young are on their own from birth.

Do the fish eat each other? Do the sharks eat the fish?
Careful consideration goes into planning what types of fish can live together at the Aquarium and into the design of the habitats themselves. The animal care team also puts a ton of energy into ensuring each animal is provided a healthy diet to ensure its wellbeing. Plan to visit the Aquarium during our next shark, gamefish or Amazon River habitat feed to learn more about the specifics.

Why do fish swim so fast?
Fish are well adapted to their specific habitats and not all fish swim fast. Fish that live in open water often have forked or crescent shaped tails to swim fast to avoid predators. Other fish, like coral reef dwellers have rounded or wedge-shaped tails to swim slowly through the rocks and corals on the reef.

How do fish breathe?
As humans, we use lungs to breathe oxygen from the air around us. Fish use gills to breathe oxygen from the water. Some fish have an organ to pump water through their gills while resting, most sharks swim constantly to pass water through their gills, and moray eels gulp water through their mouth to pass over their gills.

What happens to the fish poo?
Keeping habitats clean is a lot of work and requires a team effort. The life support systems (LSS) team at the Aquarium manages the pumps and filters on each habitat that work to filter out waste. There are also helpful bacteria in the water that break down the waste, and the LSS team routinely does water changes to control the ammonia levels in the water that can build up from fish waste. Additionally, the animal care team spends time scrubbing the walls and vacuuming the sand or gravel in the habitats to remove algae and waste. The dive team does this in the larger habitats like shark, stingray touchpool, coral reef, and others.

Is your curiosity still burning? Check to the Aquarium’s YouTube channel to learn more about the Aquarium and aquatic life.

10 More Things We Now Know About Sharks & Rays

July 28, 2025

Species Highlights

Written by Greater Cleveland Aquarium

It’s the time of year when we take a deep dive into our collective fascination with sharks and stingrays. And, as it turns out, there’s still a lot for us to learn about them.

While they’re disappearing at an alarming rate—with at least fifty percent fewer sharks and rays in the ocean today than there were in 1970 and as many as one-third of all known shark and ray species threatened with extinction—new information on elasmobranchs continues to surface all the time.

Here are just a few of the new theories and findings that have come to light over the past few months:

COLOR US SURPRISED Scientists discovered that pigment working in conjunction with microscopic guanine crystals in a blue shark’s dermal denticles (the tiny, tooth-like structures on their skin) might give the animal the ability to change hue and subtly camouflage in response to changing environment conditions.
NEW BUT VERY OLD The National Park Service announced fossils found in Kentucky’s Mammoth Cave National Park resulted in a newly identified ancient shark species—Macadens olsoni. And that’s not even close to their only shark find, by the way—in March the Park shared the discovery of a “chipmunk shark” with molar-like teeth.
TAG, THEY’RE IT Florida Atlantic University’s Harbor Branch Oceanographic Institute researchers shared they had developed a custom, multi-sensor biologging tag that was successfully field tested on the elusive and fast-moving whitespotted eagle ray, tracking how it moved, ate and interacted with its habitat.
A TOOTH COULD HOLD THE TRUTH Australian researchers determined that despite preservation, shark jaws and teeth kept in museums and other collections still had the potential to reveal where and what those animals ate when they were alive via the process of stable isotope analysis.
THEY COULD EAT WHATEVER THEY WANTED Always a subject of fascination, modern understanding of the megalodon is constantly evolving and a recent study suggested that the massive creature’s dining habits might have been broader and more opportunistic than previously believed.
SCARS REVEAL SECRETS Researchers proposed a new system for classifying white sharks’ wounds in the hopes of being able to piece together some fairly basic but still unknown information such as where they mate, where they give birth and “how they interact with prey, predators and each other.”
A TELLTALE TAIL Because not all rays have protective barbs on their tails, scientists have long wondered why they had tails at all. Researchers taking a closer look found the cownose ray tail was connected to its lateral line and contained tiny holes, suggesting it was a sensory organ that serves as a sort of antenna.
SHARK SOUNDS Scientists in New Zealand recorded what is believed to be the first-ever recording of sharks actively producing noise—the clicking of rig sharks.
TAKING A MUCH CLOSER LOOK Researchers examined the internal structure of blacktip sharks at nanoscale to find out what in their biomechanical makeup contributes to their power, resilience and flexibility.
BABY SHARKS ARE A BIG DEAL Mapping newborn whale shark sightings against oceanographic data revealed a connection between whale shark births and Minimum Oxygen Zones that ultimately could help contribute to the species survival.

Are you a shark and ray fan? Follow us on Facebook, sign up for our e-news or subscribe to our YouTube channel for more information on elasmobranchs and other aquatic life.

-Samantha F.

Sharks at #CLEAquarium!

July 16, 2025

Species Highlights

Written by Greater Cleveland Aquarium

Join Aquarist Ryan as he shares fun facts about the 4 species of sharks residing at the Aquarium in the video below!

Enjoy the video? Join us for a celebration of sharks and stingrays during Fin Fest, now – August 5.

Where Do Shark’s Teeth Go?

Species Highlights

Written by Greater Cleveland Aquarium

The Aquarium divers find tons of shark teeth during daily operations! We’re showcasing the different types of teeth they find and how they’re adapted to each species in the video below!

Join us for a celebration of sharks and stingrays during Fin Fest, now – August 5.

Talking About Rays With Curator Ray

Species Highlights

Written by Greater Cleveland Aquarium

Have you ever wanted to know why stingrays bury themselves in the sand, or how they find food? Aquarium Curator Ray P. took some time to answer those questions in the video below!

Join us for a celebration of sharks and stingrays during Fin Fest, now – August 5.

Frogs v. Toads . . . What’s The Difference?

March 24, 2025

Written by Greater Cleveland Aquarium

Have you ever found yourself wondering what exactly is the difference between a frog and a toad? While these two amphibians may look similar, they have some key differences, especially when it comes to their habitats and movement.

Northern Green Frog at Greater Cleveland Aquarium. — (Northern Green Frog)

Here in Ohio, both frogs and toads play an important role in our ecosystems, and you can find them in a variety of environments, from wetlands to woodlands.

Frogs are typically found in or near water, with smooth, moist skin that helps them stay hydrated. Their long, powerful legs make them excellent jumpers, allowing them to escape predators with ease.

Toads, on the other hand, prefer drier environments like forests, gardens and even suburban backyards. They have rough, bumpy skin that helps retain moisture. They have shorter legs, which makes them better suited for walking or short hops rather than long leaps. Despite these differences, both frogs and toads are voracious insect eaters, feasting on everything from mosquitoes to beetles – making them great natural pest control!

Next time you visit the Aquarium, be sure to check out our amphibian habitats to see if you can spot the differences and know whether you’re peering at a frog or a toad. And if you’d like to learn more, join us for our Take A Closer Look virtual tour. We’ll look closely at some of our smaller residents as we tour the Aquarium and answer all of your big questions in real-time.

5 Things I Learned About Picasso Triggerfish

December 12, 2024

Written by Greater Cleveland Aquarium

Known for its bright, distinctive bands of color reminiscent of a Pablo Picasso painting, you’re looking at the aptly named Picasso triggerfish. Here are 5 things a non-aquarist learned about this fascinating species at Greater Cleveland Aquarium.

1: Some know this species by a different name: lagoon triggerfish. Another fitting title for a fish that spends most of its time
in sub-tidal reef flats and shallow lagoons.

2: For breeding, this species forms distinct pairs. Females build the nest before laying eggs and become very territorial as they guard their future young.

3: Because of the shape of the dorsal and anal fins, this species can swim forwards, backwards and even hover in place.

4: When alarmed, the triggerfish makes a whirring sound. Researchers believe the whirring warns other triggerfish of potential danger.

5: The “trigger” in triggerfish comes from their dorsal spine, which can be raised when startled. If the fish is hiding in a small space, the spine acts as a wedge to hold them in place.

With its bright coloration and attention-grabbing name, it’s hard not to notice the Picasso triggerfish. Look for one during your next Greater Cleveland Aquarium visit.

5 Things I Learned About Northern Clingfish

Written by Greater Cleveland Aquarium

This flat, round animal is the Northern clingfish, typically found in in the Eastern Pacific from Alaska to Mexico. Here are 5 things a non-aquarist learned about this fascinating species at Greater Cleveland Aquarium.

1: With a slightly flat, depressed head, the clingfish’s pelvic fins connect to form an adhesive disk, which it uses to stick itself strongly to rocks and plants. Just to hammer home how impressive their physiology is, scientists are currently in the process of creating suction cups inspired by the northern clingfish’s disk.

2: Clingfish use their suction to steady themselves as they pull prey off rocks. Their favorite menu items include crustaceans and mollusks.

3: In terms of their predators, clingfish have to keep an eye out for snakes, gulls and even raccoons, who might snatch them up at low tide!

4: Northern clingfish reproduce by laying eggs under rocks. The eggs hatch into what are called platonic larvae and it’s the males who protect the babies.

5: A northern clingfish can survive low tide by breathing air—well, more like it absorbs oxygen through its skin, which is a useful trait for an intertidal fish.

Look for this interesting fish clinging to the glass or rocks of its habitat during your next Greater Cleveland Aquarium Visit. Nature. It’s a curious thing.

Wild, Weird & Creepy Creatures

October 30, 2024

Written by Greater Cleveland Aquarium

Why do some animals give us the creeps? As Halloween season is upon us, it’s important to stop and consider. Have you ever felt a shiver down your spine at the sight of a spider lurking in a nearby corner, or watching a snake slither away through tall grass? At the Aquarium, we like to highlight some of these less beloved animals and dig into why their reputations leave a bit to be desired.

Let’s start with an easy one. Sharks have long been branded as these violent and blood-thirsty predators, seeking out both fish and human without preference. Thanks to sensationalized popular media such as ‘Jaws,’ we were fast to believe this behavior is real. This fearsome image overshadows the fact that sharks are vital gatekeepers of their oceanic ecosystems, providing balance to the underwater world. Sharks are in reality remarkable survivors, deserving at the very least our respect, and even our admiration.

Snakes are another animal often evoking terror for humans, most likely due to their serpentine bodies and fear of their hooked fangs, which are sometimes equipped with venom. As with sharks, popular media and cultural narratives have painted snakes as malevolent over the years, moving far beyond the reputation snakes deserve. The vast majority of snakes are harmless, and would much rather escape our presence than engage with us. Many species also play critical roles in their ecosystems as both predators and prey.

Before judging animals based on their physical appearance and historical narratives, it’s crucial to stop and consider the facts. Facing natural obstacles in the world along with our persecution, negative reputations have pushed some of these species to the brink of extinction.

Join us for our Wild, Weird, & Creepy virtual program on October 30 to learn about some more of these animals, and how you could potentially help out with changing the narrative!

– Educator Matt D.