If you want a small garden pond but you live in an apartment, you don't have to give up the idea altogether. Instead, you can put a pond right on your balcony.
Choose a Container
You can use a large tub or any container that's watertight, or shop at a home improvement or garden store. There are ready-made containers available that are designed for container ponds that will work well on a balcony. You may want to invest in a pond liner, just in case the container you choose has a small flaw. This extra step can save you grief and a flooded balcony.
Place Your Small Garden Pond
Choose a spot on your balcony that gets at least a few hours of direct sun per day so that your water plants can grow properly.
Choose the Best Plants
Parrot's Feather and sweetflag are great plants for oxygenating the pond and keeping the water clear. Choose the lily variety called Mary Patricia, which is a smaller lily better suited for containers.
Choose gold fish instead of koi for a small garden pond on a balcony, because they will stay smaller in proportion with the container and will eat mosquito eggs. They must be brought in during cold climate winter months. Also, add an aquatic snail to eat algae.