>Is sand compatible with Undergravel filters? if so I might look into >it. otherwise i will use some form of fine gravel. >Jeff I think not, unless your UG-filter has really narrow slots. Sand is, by definition, 0.2-2 mm in size, gravel is 2-20 mm grain size. I know a lot of people call it sand even though it's 5 mm or more. I know that my cories want the sand, I think most Apistos prefer it but it isn't that important. I have noticed that most Apisto- females seem to do more digging if the substrate is finer. I use mostly coarse sand 1-2 mm and fine gravel <4 mm. There isn't much gravel in the Amazon, mostly clay/mud, debris or sand. Regards Fredrik L. ------------------------------------------------------------------------- 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"!