Yes it is , if i got a good year with breed fish a gonna put some more tubs into the ground.
But first i need more plants for these so the water become clean!
I attached a picture of nice floating plants that frogs like. These are cheap and multiply fast...this is what you may already be considering. The size of your water feature is small so remember the oxygen is used up by the plants- not leaving much for water creatures.
Use grasses and mulch around them-- the grasses fill in nicely- creating a visually-flowing water garden. I have a bog in mine that filters water so it draws frogs and animals and keeps the water moving.
You may want to consider a fountain- make one that 'falls' into each container and flows. Position the containers in steps. They are neat to make. And inexpensive.
Picture...