Two Roostertail Conch Shells, or Rooster-tail Conch, Aliger gallus, for sale, from Mexico.  One measures approximately 5 inches long and 3-1/2 inches wide; the other 5 inches long and 3-7/8 inches wide. They are a gastropod mollusk in the Strombidae Family of True Conch Shells.  They are found on sand and rubble in as shallow as 1 foot of water and as deep as 360 feet.  The Roostertail Conch is a tropical shell found in the Mexican waters of the Atlantic Ocean, but are primarily found in the Caribbean. Our rooster tail conch shells are a medium sized shell ranging in size from 5 to 6 inches long.  There are small knobs on the shoulders of the shell.  The aperature is long and the lips are flared.  This is the only conch species to have a narrow extension above the spire.  The exterior is molted brown, yellow and white while the interior of the shell is peach to orange and white further in.  The maximum length of the roostertail conch is 7.9 inches.