I have some assasins. Small,medium and large ones. Couldnt tell you the age though they are all mixed in one tank. The larger ones maybe not have as bright colouration due to led lights but they will still due a fabulose job at getting rid of the nuisance snails.
The Assassin Snail, or Snail Eating Snail, is a small, easy-to-keep freshwater invert completely harmless toward fish and shrimps, but quite effective in reducing nuisance snail explosions. It is also extraordinarily eye-catching in planted aquariums, featuring a bright yellow with chocolate brown striped shell.