Oak leaves as Dan stated
Oak leaves are plentiful and FREE!
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Oak trees also grow in South America. Oak leaf litter is a natural habitat for a lot of SA Dwarf cichlid. I believe there are some Apistos that will not spawn without them.
Dan , pay attention to the last statement. Because, I could not spawn the Apisto. sp. abacaxis I turned in for BAP without oak leaves, peat, and rain water. All other attempts to spawn them failed.
As far as a smell I have never had a problem with that. In fact I am still using oak leaves I collected from last April. I keep them dry and in a open bag with air circulation. I've stored and used one batch successfully for over 2 years with out fail.
They are messy but effective.