Can you put tropical fish in a goldfish tank?

* Water Temperature: Tropical fish need warm water, usually between 75-82 degrees Fahrenheit. Goldfish prefer cooler water, typically around 68-72 degrees Fahrenheit. Mixing them could lead to stress and even death for either species.

* Water Chemistry: Tropical fish and goldfish have different water chemistry requirements, especially regarding pH and hardness. Goldfish tolerate a wider range, but tropical fish are more sensitive and could be harmed.

* Diet and Feeding: Tropical fish have different dietary needs than goldfish. Feeding them the same food could lead to nutritional deficiencies in both species.

* Space and Aggression: Goldfish are larger and more active fish, potentially making them aggressive towards smaller tropical fish. Even if you get compatible species, they may fight over food and space.

Possible Exceptions:

* Small, Peaceful Tropical Fish: A few small, peaceful tropical fish, like some tetras or dwarf gouramis, might be able to coexist with goldfish in a large, well-filtered tank. However, you'll need to be careful about compatibility and ensure the water temperature is suitable for both species.

Best Practice:

For the health and happiness of your fish, it's best to keep goldfish and tropical fish in separate tanks. This ensures that each species has the ideal environment and care they need.