Fireflys are very pretty, one of my favorite bps. Another awesome snake is a brooks king snake.I loved mine, he was a great eater. A twenty gallon will be fine for a few years unless he ends up a monster. Not much heat required and very reliable eaters. Straight up gorgeous in my book, I love the black and yellow contrast on the normals. I kick myself repeatedly for selling mine..
I know Brooks king snake is considered a Florida kingsnake now, but they were called brooksi kings when I bought mine. BHB has some very nice ones.