Look at pictures of sea horses and their close relatives, pipe fish and sea dragons. There are many at yahooligans.yahoo.comScience_and_NatureLiving_ThingsAnimalsAquatic_Life FishSeahorsesSeahorse_Pictures List the characteristics these fish share with a distant relative such as the stickleback.
Get pupils to work out what features help sea horses survive in coral and sea weed.
Use the sea horse as a different example from those in standard texts on the exploitation of animals and endangered species. Get pupils to research ways in which sea horse traders can be offered other sources of income. See http:seahorse.fisheries.ubc.caconservation.html
Research control mechanisms of the rapid colour changes used in sea horse camouflage and compare these with other nervous and hormonal mechanisms.