yes it is a chinese algae eater.
They can grow from 8-11 inches at adulthood.
They stop eating algae once they reach the 5 inch size
and tend to be come very aggressive.
My sister had one and she got rid of it after it had latched onto
the side of her Oranda goldfish and was eating the fish alive.
They are well known for their taste for sushi! LOL
A better choice of algae eater for your tank would be a
bristlenose pleco, or some otto catfish.
Heres some info on the chinese algae eater for you, and your baby
platy is so cute!