How long can an Orchid (Or another flower) end submerged below dampen? I want to create a floral fish display, with a submerged flower...

I want to create a floral fish display, with a submerged flower anchored down surrounded by small glass pebbles and a floating candle on top next to little fish swimming around the submerged flower. I have spoken to the Pet Shop man and bought appropriate little fish, and own safe floating candles. All thats vanished is I'm not sure how often I would own to replace a submerged flower, I'm thinking of using orchids. any ideas which flowers would final longest under river?
Gardening ? in the order of roses?
Answers:    All organics including flowers will sufficate when immersed. I am sure you would not want to deal beside the rot and decay.

There are credible plastic and/or silk flowers that would do the job.
Blue Himalayan Poppies.direct sow or refridgerate first?
Each condition is different. You will lone find your answer if you try out your ideas.