Do solar fish really work in your swimming pool?

Residential Solar Power

I don't have a heater for my home pool, it isn't huge at about 30ft round and 4ft 6inches deep. We do have a solar cover but it is an absolute pain to use and I am looking for alternatives to a solar cover or heater for my pool.

I don't live in the western US, so we don't get constant sun and warmth, I need to find a way to use as much solar power as I can to keep my pool warm so we can use it more often.