Note that many of the monsters may need to be controlled with the Mediator's !Control ability to learn the spell, because the monster will never use it on its own in battle.
Also, some monsters don't start out with enough MP to cast the spell. In that case, use an Ether on them; that will enable them to cast the spell.
It is said you can also learn every Blue spell in the game from Apocalypse, a boss in Dimension Castle. I don't know if you can get EVERY Blue spell from him, but he does use many of them.
Want all the Blue Magic spells as fast as possible? Check out my Blue Magic Strategy Guide to find out exactly how
to get them all.
???? - Deals damage equal to caster's max HP minus his/her current HP
???? can be learned from Gogo, K. Behemoth, Kuzar, Machinehead, Wild Nack, and Tyrasaurus.
Aero - Damage enemy with wind magic
Aero can be learned from Gigas, Magisa, Mold Wind and Mukare.
Aero 2 - Damage enemy with stronger wind magic
Aero 2 can be learned from Djinn, Enkidou, Gajera, Gigas, Gilgamesh, Page 32, and Whirldemon.
Aero 3 - Damage enemy with strongest wind magic
Aero 3 can be learned from Bardandels, Cherie, Elm Gigas, Magic Dragon, The Sealed, and Tyrasaurus.
Aqua Breath/Aqua Rake - Damage all enemies with water magic
Aqua Breath/Aqua Rake can be learned from Bahamut, Chim. Brain, DarkChimera, Leviathan and The Sealed.
Big Guard - Casts Safe, Shell, and Float on all allies
Big Guard can be learned from Shinryuu and Stingray.
Blood Suck/Vampire - Absorb HP from an enemy
Blood Suck/Vampire can be learned from Abductor, BloodSlime, Bold Mani, Enkidou, Mercury Bat, Python, Radiator, Shadow, Steel Bat, and ZombieDrgn.
Blowfish - Do 1000 damage to one enemy
Blowfish can be learned from Bland Lamia, Chamcubia, Hedgehog, Lamia and Mukare.
Condemn - Sentence an enemy to death in 30 seconds
Condemn can be learned from Cursed One, Exdeath, and Unknown*.
* There are 4 enemies called Unknown: This spell can only be learned from the Unknown that is hanging from the ceiling.
Dark Shock - Halves level of one enemy
Dark Shock can be learned from Black Flame, Druid, Nile, Rock Brain, and Shadow.
Death Claw - Paralyse an enemy and reduce its HP to single digits
Death Claw can be learned from Death Claw, Gilgamesh, Iron Claw, Rock Brain, Statue, and Torrent.
Emission - Fire magic against one enemy
Emission can be learned from Crew Dust, Fire Cannon/Flame Gun, Machine Head, Mind Flayer/Mind Mage, Omega, Prototype and Triton.
Exploder - Sacrifice life of one ally to deal lots of damage
Exploder can be learned from Bomb, Grenade, Motor Trap, Prototype, Pueroboros and Unknown*.
* There are 4 enemies called Unknown: This spell can only be learned from the pod-like Unknown, and then only when they are not in groups of three.
Flash - Blind all enemies
Flash can be learned from Bella Donna, Blocks, Crew Dust, Gilgamesh, Necrofobia, Neon, Orcat and Ramuh.
Frog Song - Turn one enemy into a frog
Frog Song can be learned from Archeotoad, Chamcubia, Conago, Elf Toad, Fanfarrero and Gilgamesh.
Fusion - Transfers all of the casters HP to another party member, killing the caster
Fusion can be learned from Dilure, Mithril Dragon, Torrent and Unknown*.
* There are 4 enemies called Unknown: This spell can only be learned from the Unknown that has green ooze running across its body.
Goblin Punch - Does damage to one enemy but takes no MP. Deals more damage if the target is the same level as the caster.
Goblin Punch can be learned from Armon, Black Goblin, Gilgamesh, Gabbledegak, Goblin, and Sahagin.
Guard Off - Lowers enemy defense
Guard Off can be learned from Cursed One, Magic Dragon, Nile, Page 256, Shadow, and Ziggurat.
Level 2 Old - Casts old on any enemy whose level is a multiple of 2
Level 2 Old can be learned from Ixecrator, Magic Dragon and Level Check.
Level 3 Flare - Cast Flare on any enemy whose level is a multiple of 3
Level 3 Flare can be learned from Archeosaur, Exdeath, Ixecrator, Level Check, Lunenta and Red Dragon.
Level 4 Gravity 2/Level 4 Quarter - Casts Quarter on any enemy whose level is a multiple of 4
Level 4 Gravity 2/Level 4 Quarter can be learned from Hydra, Ixecrator, Level Check and Tricker.
Level 5 Doom - Casts Doom on any enemy whose level is a multiple of 5
Level 5 Doom can be learned from Ixecrator, Level Check, and Page 64.
Lil' Melody/Tiny Song - Casts Mini on one enemy
Li'l Melody/Tiny Song can be learned from Cherie, Fanfarrero, Gilgamesh, Mini Mage and Mukare.
Magic Hammer - Halves an enemy's MP
Magic Hammer can be learned from Apanda, Byblos and Drippy.
Mind Blast - Deals damage + paralyzes/poisons enemies
Mind Blast can be learned from Mind Flayer/Mind Mage, Stalker, and Twin Tania.
Missile - Reduce an enemy to 1/4 of its current HP
Missile can be learned from Bolt Cannon, Gilgamesh, Machine Head, Motor Trap, Prototype, Rocket, and Sol Cannon*.
* You cannot learn this spell from the Sol Cannon at the flying Lonka ruins, only the ones at the Phoenix tower. You can, however, also learn Missile from the two unnamed launchers on the Lonka Sol Cannon.
Moon Flute - Berserkes all allies
Moon Flute can be learned from Garkimasra, Gloom Widow, Mukare, Page 256 and Traveller.
Roulette - Randomly selects one character (enemy or ally) and instantly kills it
Roulette can be learned from Bella Donna, Doom Dealer and Shinryuu.
Time Slip - Puts an enemy to sleep and casts 'Old' on them
Time Slip can be learned from Cherie, Gilgamesh and Traveller.
White Wind - Heals all allies an amount equal to the caster's current HP
White Wind can be learned from Arage, Enkidou, Whirldemon and White Flame.