I changed the link to add the new one. That comment noted is not from a study it is from an extension fact sheet. There is a big difference. The study I posted is correct and provides balance to the fact sheet (more info and accuracy as to food items) and is why I posted it also. The fact sheet qualifies the statement "readily". That is exactly what I am talking about in looking closely at what effects the conclusion. They will eat what is there if hungry. A better choice of words would have been "prefer algae" IMO.