I've a pair of P.taeniatus "nange" which started off as a trio. The spare female was killed after the other two paired up. So I'd say pairs. This was in a 36" tank. Ken. ***************************** Ken Laidlaw UK Astronomy Technology Centre Royal Observatory, Edinburgh Web: http://www.roe.ac.uk ***************************** ------------------------------------------------------------------------- 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"!