Caviar can be kosher, indeed. For caviar to be kosher, it has to come from a fish that has fins and scales and must also be prepared according to Jewish religious dietary laws. The sturgeon is usually the most popular type of fish used for making kosher caviar which is a gigantic prehistoric species found in the Caspian as well as Black Sea regions.
Sturgeon, as one of its conditions, must be caught and prepared in particular ways in order to be considered kosher. Humanely killing the fish and having the caviar processed under a rabbi’s supervision are some of these requirements. Moreover, equipment used when processing the caviar should also get cleaned and sterilized following Jewish dietary rules.
Besides sturgeon, there are other types of fish such as salmon, whitefish or paddlefish that could contribute to making kosher caviar. However, the process of preparing these kinds of caviars might differ from sturgeon’s and they may not therefore be taken to be either expensive or prestigious like this latter one.
To make this determination, two factors must thus; different types of fishes used in preparation then processing methods will tell whether it is kosher or not. It is always important you read labels on products or engage with manufacturers or sellers before purchasing any specific brand of Caviar since its Kosher status may vary.