I bought two water lillys just before Xmas. First they went well but are now rotting. Help me save them please

On the 20th of december I bought a white hardy and a purple tropical water lillys (I'm not sure of the exact type). At first they seemed to be going fine but they've gone down hill quickly in the last week or so.

When I first got them home I put a fertiliser tablet in their pots and put them in an existing water feature. They seemed to be adapting well at first but soontwo leaves sunk beneath water level and looked like they were rotting. Now almost all the leaves and the flowers are in this state and I don't know what to do. They stupid water feature was switched on for a while so that may have hastened their downfall and I have seen a tiny snail-like creature on one of the leaves that I think is slowly eating it. I'm also worried their too deep in the water but I don't really know.

I know now that I went into this half-****** but I'm hoping there is some way to bring them back from the brink. If anyone has any advice I'd really appreciate it.
I bought two water lillys just before Xmas. First they went well but are now rotting. Help me save them please
Sounds like you're drowning it. I would get some fresh water, and try to let it dry out a bit. Maybe it's too warm, too?
Reply:the lilies should be at least 18" to 24" deep in the water and they require at least 8 hours of FULL sun for foliage and leaves

they do not like any moving water only still water

if your water feature is inside you probably won't be able to grow waterlilies