I put four brands of pink worms in a very large bowl of water this afternoon and here are the results:

Seducer - very bouyant, floated on top of the water.

Exude - same as Seducer - floated right on top.

Yamaguchi - fairly bouyant - stayed towards the top at first and then suspended below surface but did not sink to bottom.

Killer worms - the least bouyant of the four tested - slowly sank to the bottom and stayed on the bottom.

thanks for all the input -