Arbitration of White BLTR (Ultra Rare)

You can target 1 Fish monster you control; it is treated as a Tuner this turn. When an opponent's monster declares an attack: You can discard 1 Fish monster; change all monsters your opponent controls to Defense Position. If your Fish monster is destroyed by battle or sent to your GY: You can send this face-up card from your Spell & Trap Zone to the GY; Special Summon 1 Fish monster from your GY. You can only use each effect of "Arbitration of White" once per turn.