Elaine, I am soooo bad about fertilizing anything. I usually have good intentions but then forget rather quickly.
I can't remember the last time these were fed when they were growing in soil and they haven't been fertilized in the almost two months they've been growing in the water either. I have noticed that they've produced new roots since being in the water so if I supply them with a few nutrients they might also grace me with a bloom or two.
I'm going to make myself a note right now to get my 5 gal bucket out tomorrow and mix up some plant food for everything on the porch and the deck and I'll give these guys a tiny bit at the same time. I'm going to take them back out to the porch right now because I know if they are indoors I'll not think about feeding them.