The Long Island Aquarium and Exhibition Center in Riverhead may be one of the most visited year-round attractions on Long Island. The aquarium is home to thousands of fish, amphibians, mammals and more.

Set alongside the Peconic River, the facility opened in June 2000 -- the first large-scale aquarium to open in New York State in more than 35 years.

The Long Island Aquarium is also home to one of the Western Hemisphere's largest all-living coral reef displays.

You may have checked out the stingrays, sharks, butterflies, marmosets, sea lions and other animals, but how much do you really know about the aquarium?

Here we found 21 fun facts about the Long Island Aquarium.

LIers love the stingrays.

Credit: Gordon M. Grant

The most popular exhibit at the Long Island Aquarium is Ray Bay. You can touch southern stingrays, cownose rays and Atlantic stingrays. For a small fee, you can even feed them. There are scheduled feedings every day; outdoor Ray Bay is only open July through September. (The second and third most-popular exhibits are the sharks and penguins.)

The murals at the Long Island Aquarium feature hidden numbers.

Credit: Long Island Aquarium

Each of the murals in the Long Island Aquarium has the number 33 hidden somewhere. It's the artist's trademark. See if you can find the hidden numeral 33 in this photo.

The Japanese snow monkeys love to make snow balls.

Credit: Long Island Aquarium

The Long Island Aquarium's Japanese snow monkeys are two sets of brothers: Zepp and Ozzie, and Peeko and Jorako. They are outside all the time, with a heated pool and waterfall. In the winter, they love making snowballs.

The butterflies like to quench their thirst.

Credit: Johnny Milano

The butterflies are given Gatorade as a supplementary food source. They only like orange -- no other flavors.

There are more than a dozen penguins.

Credit: Long Island Aquarium

The aquarium is home to 16 African black-footed penguins. They will lose every feather and grow in new ones for each upcoming year during mating season.

The Marmosets like to eat Fluff and Honey Nut Cheerios.

Credit: Long Island Aquarium

The three Geoffroy's marmosets, tiny monkeys that live at the aquarium, are related. Zephyr is the mother, and her twins are named after cheese: Queso (male) and Ricotta (female). They eat a variety of fruits, vegetables and insects -- but their favorite things to eat are Fluff and Honey Nut Cheerios.

Tropical fish make their way to the aquarium.

Credit: Long Island Aquarium

Every summer, the Gulf Stream's current comes up this way, bringing warmer temperatures and tropical fish to local waters. The Long Island Aquarium will go out and collect animals throughout the entire summer, and they can be viewed in the Gulf Stream Rider exhibit located in the Rescue Center.

You can sleepover with the sharks.

Credit: Long Island Aquarium

The Long Island Aquarium hosts family-friendly sleepovers throughout the year. Kids can sleep up close and personal with the animal exhibits, take a tour of the aquarium after dark, design a craft to take home, watch a movie (with snacks) and more. Dinner and breakfast are served; check the aquarium's website for event schedule and pricing.

Many butterflies prefer to remain hidden.

Credit: Gordon M. Grant

Don't rush through the butterfly exhibit: Instead, look high and low beneath plants and in the dark. At any one time, there are 40 to 50 species of butterflies flying in the aquarium's exhibit. Although the ones fluttering around the flowers steal the show, there are many, many butterflies that prefer to remain hidden in the undergrowth.

You can snorkel on Long Island.

Credit: Jeffrey Basinger

You can snorkel at the Long Island Aquarium. The attraction's outdoor Pirate Snorkel Adventure tank teems with fish, stingrays and even some harmless sharks. For about $60, you can swim among sea life in the large saltwater tank, which is about 8 feet deep.

Some of the animals arrive via FedEx.

Credit: Long Island Aquarium

Nila, the aquarium's new sea lion, was rescued in California. She flew via FedEx along with her trainers to New York.

Admission on your birthday is free.

Credit: Gordon M. Grant

Visit the Long Island Aquarium during your birthday week and enjoy being admitted free. Adults must show a valid photo ID, and children need to bring a copy of their birth certificates. You have seven days before or after your birthday to receive free admission.

The LI Aquarium is home to the world's largest moths.

Credit: Long Island Aquarium

The Long Island Aquarium is home to Atlas moths. It's one of the largest moths in the world, with an adult wingspan that can range from 9 to 12 inches.

The parrots are high maintenance.

Credit: Long Island Aquarium

To keep the parrots in the aviary happy, the aquarium brings foliage and branches for them to play with and chew on each week. Most of the birds in the aviary have names, and individual birds can be told apart based on specific feather colors as well as by personalities and behaviors.

Early morning is the best time to see butterflies.

Credit: Long Island Aquarium

The Long Island Aquarium doesn't breed the butterflies. They are purchased as chrysalises and shipped there weekly. Be sure to get to the aquarium when it opens at 10 a.m. This is the best time to see butterflies emerging from their chrysalises in the butterfly lab window.

Many baby Cuttlefish are hatched daily.

Credit: Long Island Aquarium

The cuttlefish on display at the aquarium -- currently Sepia bandensis -- have produced eggs in the exhibit, and there are babies hatched just about every morning.

Some of the sea lions are related.

Credit: Long Island Aquarium

Sea lions Java and Bunker are half brother and sister. Sea lions, which get their name from their loud roars, barks and honks, put on quite a show at the Long Island Aquarium.

The aquarium houses frogfish, lie-in-wait predators.

Credit: Long Island Aquarium

The Long Island Aquarium has some frogfish on display in Poseidon's Treasure Room. They have the fastest mouth known to all fishes. They are predators that lie in wait and can snatch a fish from a school without any of the other fish noticing.

Ladybird beetles help control pests.

Credit: Gordon M. Grant

Once a month, the aquarium incorporates almost 18,000 ladybird beetles in the butterfly exhibit to help control the spread of plant pests. A mist rains down periodically throughout the day to help raise the humidity in the exhibit space and simulate tropical rain forest conditions.

The insect zoo features dangerous arachnids.

Credit: Dominick Chiuchiolo

The aquarium has some of the most dangerous arachnids on Earth in its insect zoo, including the Brazilian wandering spider, black widow spider and African fat-tail scorpion.

The seals strike a pose.

Credit: Long Island Aquarium

At the Long Island Aquarium, you'll find seal statues on the rocks of the seal exhibit. The statues are modeled after pictures of seals that live at the aquarium.