Cardinal tetras are fun. I have 6, and it's really cool when they come up for food.so in my 10 gallon, I have six cardinals, and one male betta!
Cardinal tetras are pretty..I was thinking ember tetras though because they are the smallest tetras..They only get to be about .75-.80 inch. I believe dwarf rasboras get to be about the same size.They stay pretty small..
I may just wait until I get my 29 gallon up and running..maybe I will have a big tank full of dwarf cories and dwarf rasboras..and ember tetras..