“I’ve had a problem retiring,” John Young says.

He and his wife, Karen, sought a new project after selling a successful home services business three years ago. They opened Picasso Exotic Aquatics in Leawood’s Park Place development (115th Street and Nall Avenue) in 2011. These days, the couple spend their days in a magical underwater world of color, pattern and movement, tending myriad tanks of exotic fish and colorful coral.

“People call us Leawood’s aquarium,” Karen Young says. The shop has become a destination for school field trips and photographers as well as customers in search of what John Young calls “a little piece of ocean” for their homes.

Q. What drew you to aquariums?

A. If you’ve got stress in your life, aquariums are wonderful things. Fifteen years ago I had an aquarium built into the wall at my home. Karen’s had aquariums since she was a kid. Every time you look at an aquarium you see something you haven’t seen before. The fish interact like they do in the wild. Where else can you be this close to raw nature?

Q. I see you have both fresh and saltwater tanks. Many people have the impression that freshwater is easier.

A. Now with the technology in lighting and filtration for saltwater, if somebody knows how to take care of fresh they will be able to do salt. Many of our clients have us maintain their aquariums. We have 10 employees with a total of more than 50 years of experience.

Q. You have an amazing variety here. Tell me about some of them.

A. We carry more than 300 types of fish and coral. Some of the freshwater varieties include neon tetras, discus fish and angel fish. We have a saltwater predator tank with lion fish, stingrays, sharks, eels and puffers. In other saltwater tanks we have spotted boxfish, dogface puffer fish, seahorses, chocolate chip starfish, cleaner shrimp and garden eels.

The eels are like Whac-a-Moles. They measure 18 inches but burrow into the bottom so you only see a couple of inches of them above ground. Our rose anemone split into 10 and has progeny in several aquariums. We named the store for the Picasso triggerfish, the state fish of Hawaii.

Q. Do you have a specialty?

A. Live corals, including hammer, frogspawn and rare chalice corals. We try to have something for everyone, and we can grow unusual corals. A baby coral costs $17, and some parents bring their kids in to pick a coral every month. They can see it grow. It’s like planting a tree. Some corals live centuries.

Q. Who should have an aquarium?

A. Aquariums are for all ages — elderly people who want a pet but don’t want the responsibility of a dog or cat. Kids are mesmerized by them and will stand still for 10 minutes. We have a dentist who put one in his waiting room so people can lose themselves in the aquarium instead of what they’re there for. Aquariums are for everyone, unless you’re traveling 80 percent of the time.

Q. What kind of investment is required?

A. An eight-gallon beginner aquarium with a light and filtration system and stand costs $197. Then you add the fish and coral. You can get a saltwater aquarium beginning at $300 and going up to $150,000 for a large tank with exotic fish and rare corals from all over the world. We even have a three-gallon aquarium, but (with the open top), it’s not good if you have a cat.

Q. Can you lay out some rules for success?

A. Not too many fish for the size of tank, and you don’t want to overfeed. You need to do a water change every week or every other week — replace 20 percent of water using a siphon. And you want to keep the tank away from direct sun.

Q. You mentioned you get visits from school field trips. What are some of the benefits for children?

A. You can teach responsibility by having them clean the glass and feed the fish. They learn about the ocean and the different names for coral and fish. We’ll let them hold and pet the starfish and see what it feels like. For children with autism and ADD, aquariums help focus their attention.

Q. How do you keep the fish from fighting or eating one another?

A. We make sure everything is compatible. For instance, the lion fish is used to eating other fish. We train them to eat frozen food in the store. We quarantine them and make sure they’re ready before we let them go to a client. For a reef tank with live coral, we put in reef-safe fish. We use decorative coral in a marine tank for predators.

Q. I see you have tanks with different themes

A. There’s a freshwater tank with a river theme and an Oriental tank with a Buddha figure and goldfish, which are a symbol of wealth and good fortune. We have a desert-theme tank. Karen is our interior designer of aquariums. She can custom-design a tank to match a home’s decor. In a red room, you could have a tank filled with red discus.

Q. Have there been any big changes in aquarium technology?

A. LED lights. In the last two to three years that’s one of the biggest changes. Before, the lights were high-energy-consuming. LEDs are cooler and consume less energy, and the corals like it more.

Q. Do you two have a favorite fish?

A. The blue spot stingray we just got in is incredible. He has bright neon blue spots, and he buries himself, except for his eyes poking out, looking at you. He’s so cute.

Alice Thorson, The Star