The upped version is OP, definitely. Even if you don't pay the upkeep, it's 18 damage over 2 turns for 3 quanta...
aside from that, there's no actual explanation as to why the anglerfish loses 3 hp every turn... cards in this game are supposed to be believeable and 'realistic' (in a fantasy world sense), and i just don't see the ability of the upped version to meet that requirement.