Historical clue formulations

• Suckerfish that attaches itself to sharks — 2020-10-28
• Sea sucker — 2018-08-09
• Fish that can attach itself to a boat — 2015-10-05
• Fish that attaches itself to a host — 2013-05-11
• Whalesucker — 1998-07-26
• Fish that hitches rides — 1997-10-12