Yes fish ponds can survive without plants as long as oxygen is added. Shelter is provided by the rock formations, and the fish are fed daily. Plants are around the pond providing shade thoughout the day, with never more than 60% coverage. Beautiful pond, all clear, can see all my fish. I love it and don't know that I will ever add plants back into the water again. Who knows may change my mind in another year or so. But for now I am enjoying the clear water and the beautiful fish for a while.