>>leave the cap on and make a smooth-edged hole in the cap such that only the fish that are fry size can get in.<< Nice touch. You could actually have a collection of caps with different size holes to accomodate different species or fry at different time of development. Bill Vannerson McHenry, IL http://ourworld.compuserve.com/homepages/william_vannerson ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@majordomo.pobox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@majordomo.pobox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!