Historical clue formulations

• Fish in the genus Hippocampus — 2021-06-22
• Fish with a prehensile tail — 2020-06-05
• *Swimmer with a prehensile tail — 2015-12-16
• Fish with a long neck — 2013-04-07
• Hippocampus hippocampus, e.g. — 2012-01-22
• Mount for the god Neptune — 2011-07-10
• Fish whose male carries the eggs — 2010-11-05
• Cousin of a stickleback — 2009-05-29
• Equine-looking fish — 2007-10-29
• *Underwater creature whose males give birth — 2007-07-17
• Fish that sings when mating — 1997-06-22
• Fish of which the male carries the fertilized eggs — 1997-01-23
• Fish that swims upright — 1996-09-09
• Fish that can twine its tail — 1996-06-16
• Fish whose male hatches the eggs — 1996-03-28