Rybníček was formerly part of the German Empire. In the German Empire, the place was called Rybníček.
The place is now called Rybníček and belongs to Czechoslovakia.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Rybniček | Austro-Hungary | Časlau | before the Treaty of Saint-Germain |
| Rybníček | Austro-Hungary | Časlau | before the Treaty of Saint-Germain |
| Rybníček | Czechoslovakia | Čáslav | after the Treaty of Saint-Germain |
| Ribnitschek | German Empire | Tschaslau | 1939 |
| Rybníček | German Empire | Tschaslau | 1939 |
| Rybníček | Czechoslovakia | Čáslav | 1945 |
| Rybníček | Czechoslovakia | Východní Čechy | 1992 |