Close. Fish roe, sometimes known as fish eggs, is what it is.
Caviar is salt-cured roe from sturgeon or other sturgeon-like fish. Tobiko (tropical flying fish roe), masago (capelin roe), or ikura (salmon roe) are the most common fish roe used in sushi (salmon roe).
The masago is the tiniest and generally has an orange tint.
Tobiko is slightly bigger and may be coloured or left in its natural red/orange hue.
Ikura is the biggest and orange-colored of the three.
I’m not joking when I say ikura is the largest; the size difference between masago and tobiko is one thing, but here’s a photograph of a gunkan maki that uses both green wasabi tobiko and ikura.
Yes. In a way. Caviar is made from of sturgeon eggs or roe. The little balls you see on sushi are roe or eggs from a variety of fish.
Tobiko (flying fish roe) is a reddish orange roe that is commonly utilized. Some are stained black with squid ink, while others are tinted yellow with yuzu. Masago (smelt roe) and capelin are also utilized.
Ikura are the bigger orange eggs you may have seen (salmon roe).