The number of tanks necessary depends on your goal. If you want to keep a breeding pair, and replace them when they die with their own progeny, then probably three tanks would be necessary. The more involved you get with a given species/population, the more space they will need. Bob Dixon ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!