I just found this filter feeder and thought that it was the coolest thing ever. Do you think it would be possible in a 55 gallon with 2 bichirs? It buries itself, so I can't imagine the bichir would try very hard to eat it.
http://www.liveaquaria.com/product/prod_display.cfm?c=1075+1642&pcatid=1642
http://www.liveaquaria.com/product/prod_display.cfm?c=1075+1642&pcatid=1642