Ari was unsure of what to do now that he had managed to enter Diagon Alley's infamous pet shop. The only logical thing would be to purchase an animal companion, right?
First, the noise in the shop made Ari's muscles tense. His family had never kept a pet for as long as he'd been alive, so the barking of kruppies and snarls of angry cats set him on edge. It was just another addition to the list of things he wasn't used to.

That was the first decision he made. If he were to walk out of here with a pet, it would be a quiet pet.
Finding a quiet animal in this shop was easier said than done, however. The many cages that lined the walls and hung from the ceiling contained creatures that could prove to definitely startle someone.

"Finding everything okay, young man?" An older lady's voice asked from behind a box in the corner.

"Um, yes ma'am," Ari replied, raising his voice to be heard over the noise of the animals around him.

"Good! If you need anything, please feel free to ask my husband or I any questions, dear."

Ari let a sigh slip out as he continued to wander the menagerie, feeling disappointment bloom the more and more he looked. Maybe he'd walk out of here empty handed. It wasn't mandatory to have a pet after all. There were plenty of students at Hogwarts without pets.

And then he saw it. The back wall was lined with fish tanks.
A fish was perfect. They were quiet, didn't shed, still carried a great amount of responsibility for the owner, and minded their own business. A fish definitely suited Ari.

He quickly made his way to the back, scanning over the tanks of fish. There was anything from classic pebble-filled bowls to larger rectangular aquariums to hold multiple fish. Ari wouldn't deny it, but he was surprised at the variety of tanks he saw.
However, despite the numerous sizes and shapes of tanks, he could only find one type of fish. It was a typical goldfish, the type one might find in an aquarium at the hospital or on muggle cartoons. There were many bags of goldfish, some fish larger than others. They all looked anxious as they swam about in their small plastic bags, waiting to find a more open environment.

"Which one?" He thought out loud, looking at the fish. He wasn't sure one would catch his eye, but sure enough, he found himself being proven wrong.
The fish on the far left watched him curiously, and Ari leaned in closer to look at the fish. It swam up to the top of the bag. Its mouth touched the surface of the water, and tiny bubbles appeared on the water.

It made Ari stop and think for a minute. It made him think about the wonder of how a fish could extract the oxygen from water to breathe. Why couldn't humans do that? And why couldn't fish breathe out of water? Technically speaking, they breathed oxygen like humans did. So why couldn't fish live on land, and why couldn't humans breathe underwater?

The fish came back down to level with Ari's eyes, and its own eyes darted around, taking in the features of his face. The fish's black eyes stared back into Ari's own shade of blue, which were watching the tiny scaled gills open and close. Ari was mesmerized, and he knew he had to have this fish.

Very gently, he picked the bag up with one hand and picked up a fish tank, holding it under his arm, and slowly walked to the counter. The goldfish inside swam around, now unsure of what to do as its environment moved around it.
"Miss, I believe I'm ready to make my purchase," Ari said to the same old lady that had greeted him before. He placed the tank and the water-filled bag on the counter, then reached into his pocket and placed the money on the counter. Within two minutes, he was walking out of the shop with a new friend to keep him company during his stay at Hogwarts.

"Maybe you can teach me how to breathe underwater," He laughed.