I never have any luck without gravel or sand in my tanks. Considering how much more are you provide for the bacteria to grow on with substrate I think of it as a time-saver. There may be more work to clean the sand but I don't have to do it as often. I also never seem to get my plants to survive in bare tanks and I really like to have java moss thrive in my fry tanks. Just my experiences. I guess if you have a really good filter with a lot of surface you can compensate for the gravel but my fry tanks tend to be quite small and I can't afford a canister filter (Eheim Ecco? the smallest?) for each... Fredrik -- Fredrik.Ljungberg@saab.se Flutter and Loads Department, Saab Ab voice +46 13 18 54 60, fax +46 13 18 33 63 ------------------------------------------------------------------------- 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"!