Special Summon this card to your opponent's field (but shift control to its owner during the End Phase of this turn), and if you do, send that targeted monster to the GY
change it to face-up Defense Position, and if you do, change this card to face-down Defense Position, then, if the targeted monster was a "Ninja" monster, except "Mitsu the Insect Ninja", negate that opponent's activated effect
From versatile synchro monsters like Ravenous Crocodragon Archethys, to incredible combo tools like Nimble Angler, there are a plethora of Fish-type monsters that have been used in meta decks over the years, and many of the monsters in this type still have merit in a variety of rogue competitive decks to this day

The side deck is a work in progress, mostly you can ignore it, but I will go over it briefly if you care for it: Main Deck Total: 40 Monsters: (22) 3 Fluffal Dog 3 Edge Imp Chains 3 Fluffal Bear 2 Edge Imp Sabres 3 King of the Swamp 1 Fluffal Owl 2 Fluffal Sheep 3 Fluffal Mouse 2 Fluffal Wings Spells: (18) 2 Galaxy Cyclone 2 Frightfur Fusion 1 Raigeki 3 Fusion Conscription 2 Polymerization 2 Dark Hole 2 Dark Fusion 1 Frightfur Factory 3 Toy Vendor Extra Deck: (15) Fusions: (11) 2 Frightfur Sabre-Tooth 1 Frightfur Leo 1 Frightfur Bear 2 Frightfur Wolf 3 Frightfur Tiger 2 Frightfur Sheep XYZs: (4) 1 Constellar Ptolemy M7 1 Adreus, Keeper of Armageddon 1 Castel, the Skyblaster Musketeer 1 Wind-Up Zenmaines Side Deck: (15) 3 Gorz the Emissary of Darkness 3 Mystical Space Typhoon 3 Forbidden Chalice 3 Prohibition 3 Royal Decree Monsters: As far as the monsters go, its hard for me to say there is any possible better way to have the monster lineup in this deck

You can target 1 Fiend monster in your GY, except "Reporter from the Underworld"