Are all black eggs caviar?

NO. Just like Champagne is Champagne and all the rest is Sparkling Wine, true Caviar comes from 27 different types of Sturgeon. everything else is called Roe. You can find Roe from many other types of fish like salmon, trout, capelin, swordfish, whitefish, etc. Tobiko on sushi, for example, can be artificial and commercially produced. It takes Sterling 6 1/2-10 years to raise the White sturgeon (that is native and our broodstock spawned from fish from the Sacramento River) which is why all Roe is not alike. These prehistoric fish have no comparison, Caviar is Caviar.