1 to 2. According to Health Network, the fish tank is only 10 to 20 liters, so it is best to keep 1 2 clownfish, otherwise it will affect the health of clownfish. Clown fish can be kept in small fish tanks, but attention should be paid to mastering the number, breeding skills and maintenance methods of clown fish, so that clown fish can live a better life under the condition of ensuring health.