Overwintering tropical water lilly
 

I have a red flare lilly that I have managed to overwinter indoors for
the last 2 winters. With a plant light and a guard to keep the
goldfish from eating it, it just barely survives until spring. My
question is, should I divide it? And if so, when? It is in the same
pot that it was in when I bought it which was an 8 or 9 inch hanging
basket.

Also, does anyone know if thalia is hardy is zone 6. I forgot to ask
before I added some this past spring.