Tobiko are actually not
naturally
orange. They are
dyed any
myriad of
colors, usually orange or
red, in order to make them more interesting and
appealing. They have a slight
salty taste that is not
fishy and very pleasant.
Ikura, or
salmon roe, are naturally orange, however.
Many
restaurants of the
cheaper sort substitute
masago, which is
smelt roe, for the genuine article. This is one of the ways you can rate a place. If they use actual tobiko, they are on the way to being good.
Tobiko that has been
steeped in
wasabi and has an
intense green color is called
wasabi tobiko. It is quite a
nostril clearer.
Fans of wasabi tobiko often refer to it as
pleasurable pain.