i know this post nothing to do with glow, but i got aquarium first time in my life

I got aquarium today , i never thought i will buy one.. but yesterday i went in a shop and i saw so many beautiful aquarium there, so i though i will also buy one starter kit, i bought this one 20 gallon , and decorated it today and after one week i will put fishes in this, can any one suggest good and beautiful looking  fishes , who survives long time and play alot and dont fight or kill each other( i have no idea about fishes)  , so it will be good time pass for me, i stay at home all the time.