Q: Airport shows all nearby networks. Can I fix this? If so, how? Do I need to?

No, there is no way to fix that, it is just normal.

It won't effect your network and internet speed.

Can I fix this? If so, how?

Only by moving away.

The degree to which your wireless network is being affected by the presence of competing wireless networks can be determined by using Apple's Wireless Diagnostics: About Wireless Diagnostics - Apple Support. Hold an option key while clicking the Wi-Fi icon.

I suggest you do not specify a separate wireless network name for its 5 GHz network, unless you have justification for doing so.