Reddit mentions of The 101 Best Freshwater Nano Species: How to Choose & Keep Hardy, Brilliant, Fascinating Nano Fishes, Plants & Invertebrates (Adventurous Aquarist Guide™)

I would recommend against such a small saltwater tank for a beginner. Saltwater can be quite easy, but not in such a small tank.

Read this information on fishless cycling to get the tank ready. My recommendation would be to get small colorful fish, like those found in this book

If you really want to do saltwater, it is worthwhile to return the 10 gallon kit and pick up a 40 gallon or larger tank. That would allow you to keep a clownfish pair, and a couple of chromis or firefish - all of which are very colorful and easy to care for.

I have 2 ten gallons. If I had the room, I would go bigger. The bigger tank gives you greater dilution. And a lot of the little nano fish are easily affected by changes. I'd love a 20 long.

But, yes, a 10 gallon is fine. Suggest that if you want a neo shrimp colony you'd better have a ton of plant cover like carpet unless youhave only Otocinlus (which really need more space than a 10). If it fits in the fishes mouth they will/can eat it and shrimplet newborns are the size of a dash mark.

I LOVE the dwarf cories, i have habrosus. pygmaus are more mid-water swimmers.

BEST thing? Get Rachel O'Leary's book 101 Nano Fish on Amazon. It is a bible for nano fish. Worth every penny! https://www.amazon.com/Best-Freshwater-Nano-Species-Invertebrates/dp/0982026250/ref=sr_1_1?ie=UTF8&qid=1525672581&sr=8-1&keywords=rachel+o%27leary
I've got 10 nano tanks and they are all ten gal and under, but I WISH I had a 20 long, so if you have the room go with a bigger tank and smaller fish :)