My parents are not dog people and I'm allergic to cats. Needless to say, my family's pet of choice was always the barely cuddly, but often colorful, fish.

We never had a super fancy fish tank—just one that would hold five or 10 pet store guppies. Taking care of the fish never taught me major life lessons of responsibility. It did, however, teach me the trick to making a smooth employment transition to a small business.

When you have a new fish, with her fish-world and water all sealed in a ballooned baggie, you cannot simply dump her into your existing tank and hope all combine peacefully. No, you must place the baggie inside the tank, let the new and original fish friends learn of each other's existence first and let the two ecosystems' water adjust to a similar temperature. Then, after some time, you can carefully combine them. You must delicately tip the new fish—water and all—into the larger fish tank and hope that no one goes into shock or is literally eaten alive.

The same goes for your start up. I joined Etsy as the 17th or 18th employee and, four years later, we're well over 200. Keeping the company culture and selecting the right personalities to fit this growth is important.

When I talk with potential candidates, I try to see how they would “swim” with our team. Will the candidate cannon ball into the pool and cause too many waves, or will they slowly adjust (and allow us to do the same) to make an easy transition?

It's not easy to start a new job. Especially when you're the new kid in town or, to overdo my analogy, the new fish the pool. If the company, its existing team and the new employee work together, the waters will likely stay calm and productive.  

And I really wish I had a dog growing up…