Yes, but under current law in most states they cannot get married.
The question does not make sense. The correct grammar is "a fish" not "an fish."
Starfish are aquatic invertebrates but are oftenly called "Echinodermata" or the class Asteroidea. Happyanswers56: Starfish are aquatic invertabrates. so it's right.
A fish is one fish and fish fish is two fish.
chum