This card was nearly useless in the TCG when it was first released, because only "Zone Eater" had been released in English, although it requires 3 Fusion Materials. Therefore, it couldn't be Fusion Summoned till the two other materials were released.
This is the only Fusion Monster that is a Sea Serpent-Typemonster. However, most Fusion Monsters always have at least one Fusion Material monster with the same type as the Fusion Monster, but as for "Aqua Dragon" (being a Sea Serpent-type), none of its Fusion Material monsters ("Fairy Dragon", "Amazon of the Seas" and "Zone Eater") are Sea Serpent-Type. Another monster with such oddity is "Skull Knight", which is a Spellcaster-Type, but its Fusion Material Monsters, "Ancient Brain" and "Tainted Wisdom" are Fiend-Type.
This card's name and appearance is aesthetically similar to "Water Dragon".