Duoterion (LEDU-EN037) - Legendary Duelists 1st Edition Condition:Heavily Played You can only Special Summon

You can only Special Summon "Marincess Sea Horse" once per turn this way

Card TextTribute 1 Fish-Type monster to target 1 card on the field

you can activate it this turn

but if it does so using this effect

Duoterion (LEDU-EN037) - Legendary Duelists 1st Edition Condition:Heavily Played You can only Special SummonTypeDinosaur Effect Monster AttributeWATER Level Rank5 ATK DEF2000 1400 Card TextYou can discard this card; add 1 "Bonding" Spell Trap from your Deck to your hand. If this card is Normal or Special Summoned: You can target 1 "Hydrogeddon", "Oxygeddon", or "Duoterion" in your GY; Special Summon it. You can only use each effect of "Duoterion" once per turn.