Answer: grenadiers

AnswerCrossword Clue
GRENADIERSOriginally, they were missile throwers.
GRENADIERSRattails of the deep seas
grenadiersGRENADIER, originally, a soldier who threw grenades; then, a member of the first company of every battalion of foot-soldiers
grenadiersA common bottom-dwelling fish with a large head, a long tapering tail, and typically a luminous gland on the belly
grenadiersA soldier armed with grenades or a grenade launcher
grenadiers(in the UK) The first regiment of the royal household infantry