Lighting is actually not the biggest concern in this situation. Tank size eliminates the possiblility of successfully keeping much of the anemone species commonly sold in the trade. They need a rather large water volume and even if the parameters are kept stable will still be a concern.
If you do not intend on keeping fish, I might suggest a Cerianthus sp.
Still a concern to neighbours but not nearly as challenging or demanding as your typical anemone species as long as it's fed appropriately