Stocking Advice

I'm planning on getting a 20 gallon long with a good amount of plants. I was hoping to get 6 or 7 dwarf neon rainbow fish, and a small school of cardinal tetras. I've read some conflicting information about the size tank the rainbows need, some say 20, and i've seen some as high as 55. I just want some input on whether my tank is an appropriate size for that many rainbows, and if I could also include the tetras.

 

rainbows are very active and therefore i don't recommend 7 for a 20. They also are going to have a heavier bioload since they are so active. Save the rainbows for a larger aquarium, and go with the cardnials. Possibly you could put in some corydoras at the bottom.