We have two different kinds of fish in the pond. We have guppies in the top pool and large mouth bass in the lower pool to help set up the ecosystem. Guppies breed abundantly in the summer. The old ones wash down to the lower pool and serve as food to the bass. The bass control the mosquito population. Guppies are tropical fish sho they don't survive the winter. During the winter the bass go dormant and they don't feed.
We have three large mouth bass in the lower pool. In 2000 they were less than an inch long when they came to live in the pond. Their names are, in order of size, Speck, Mini, and Timi. Speckly is now the largest one at about 6 inches long. His speckles are prominent and they change throughout the seasons. He is the most aggressive one. Mini is about 5 inches long. Timi is slightly smaller than Mini. Timi is short for "timid". He likes to hide under the pots. He is also the smartest one. We once found him in the top pool cleaning out the guppies. At the beginning he would not come out at feeding time. They are now very tame and will bite your finger. They also take food from chopsticks.