Tireless Angler

Whenever an Island or Swamp enters the battlefield under your control, draft a card from Tireless Angler's spellbook.

Alchemy: Innistrad

Whenever an Island enters the battlefield under your control, draft a card from Tireless Angler's spellbook.

The problem wasn't that fish had learned how to fly. It was that sharks had adapted to follow them.

Mystic Skyfish

Whenever you draw your second card each turn, Mystic Skyfish gains flying until end of turn.

Nadir Kraken

Whenever you draw a card, you may pay {1}. If you do, put a +1/+1 counter on Nadir Kraken and create a 1/1 blue Tentacle creature token.

Kruphix hid the most dire prophecies about humankind where humans would never find them and tritons wouldn't care to read them.

Sigiled Starfish

{T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Stinging Lionfish

Whenever you cast your first spell during each opponent's turn, you may tap or untap target nonland permanent.

Voracious Greatshark

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, counter target artifact or creature spell.

Spined Megalodon

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever Spined Megalodon attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

To an explorer, a priceless treasure. To the crab, a rock to call home.

Ruin Crab

Landfall — Whenever a land you control enters, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

After drownings, devourings, and one highly unpleasant algae infestation, unsupervised portal use on campus was banned.

Wormhole Serpent

{3}{U}: Target creature can't be blocked this turn.

Pouncing Shoreshark

Mutate {3}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Whenever this creature mutates, you may return target creature an opponent controls to its owner's hand.

Archipelagore

Mutate {5}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, tap up to X target creatures, where X is the number of times this creature has mutated. Those creatures don't untap during their controller's next untap step.

Sea-Dasher Octopus

Mutate {1}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Whenever this creature deals combat damage to a player, draw a card.

"As the storm waves crushed my sailors, I cried out to Thassa. The next time I saw them, hard shells encased them, and they swam away to safety."
—Siona, captain of the *Pyleas*

Riptide Turtle

"Gleams like moonlight on water drew us through the storm and toward our doom."
—Siona, captain of the *Pyleas*

Serpent of Yawning Depths

Krakens, Leviathans, Octopuses, and Serpents you control can't be blocked except by Krakens, Leviathans, Octopuses, and Serpents.

"Come on, it's not even that deep!"
—Gorin the Brazen

Moat Piranhas

"Captain, I think that island is following us."

Fleet Swallower

Whenever Fleet Swallower attacks, target player puts the top half of his or her library, rounded up, into his or her graveyard.

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.