Hi,
Do you know what kind of algae eaters you have? If they are chinese algae eaters then you could be in for a shock. I was sold 2, under the name of 'gold algae eaters' and put them in a 15g tank. Everything was peaceful for a while and then they started attacking my platies. It was at this point that I found out they were agressive. Apparrently if there is not enough algae they will attack the slime coat of other fish. Also they will go for their eyes.
They can grow to 10" each too. I took mine back straight away. Keep an eye on your guppies.