The most mis-housed pets in the hobby
Goldfish & coldwater
Goldfish are coldwater fish that get big, live for years and produce a huge amount of waste — the opposite of a disposable bowl pet. Housed properly in a large, well-filtered tank or pond, they are wonderful, long-lived companions.
2 species on Finfern · 2 with a full care guide.
💧 Get the water right: No heater needed — but a big, heavily-filtered volume is essential for their heavy bioload.Care model: Coldwater (goldfish) tank
- Fancy GoldfishCarassius auratusThe round, ornamental goldfish — a long-lived, messy coldwater pet that needs far more tank than a bowl.
- Common GoldfishCarassius auratusThe classic single-tail goldfish — a pond fish at heart that reaches a foot long and lives for decades.
Plan a goldfish & coldwater tank
Our free tools use these species' real, sourced care data — no guessing:
Stocking calculator →Compatibility checker →Which fish suit your water? →