Yeah, GW names their Hive Fleets after mythical monsters. Kraken was a vicious sea monster, Leviathan a generic term for anything huge, same for Behemoth. I suppose Titan would be logical, but I think I've seen that one floating about the boards here somewhere.
Basically, any name that relates to Alien-ness or Implied threat sounds good. A notable fleet is Michael Casavent's Hive Fleet Phage, (his website has an extensive database of battle reports, and his win/loss ratio is impressive to say the least. I'd recommend studying them to see what he did, even though the rules are 3rd edition.)
My fleet is Hive Fleet Wraith, which fits my army fluff as it's a small splinter of Leviathan that has eluded destruction for years, striking and disappearing.
As long as it sounds someway cool, go for it!