Zoo Med Laboratories Plankton Banquet Block Feeder Mini (3 Pack) 18 Blocks Total (3 Packs with 6 Blocks per Pack) Zoo Med Laboratories Plankton Banquet Block Feeder Mini Time Release Feeding Block Lasts 3 To 14 Days Depending On Block Size. In Addition To Weekend And Vacation Feeding, It Is Also A Great Daily Feed Source For Problem Feeders Like Gourami's And More. Also very useful for small fry which do best when constantly feeding.