Here are some terms commonly used:
* Ornamental fish: This is a broad term encompassing any fish kept for aesthetic purposes, whether in ponds or tanks.
* Aquarium fish: This term typically refers to fish kept in tanks, though it can sometimes encompass pond fish as well.
* Pond fish: This refers specifically to fish kept in ponds, often hardy and cold-water species.
* Goldfish: This is a specific type of fish commonly kept in ponds and tanks.
* Koi: These are a type of carp specifically bred for their color and patterns, popular in ponds.
Ultimately, the best term to use depends on the specific context and the type of fish you're referring to.