Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Wonderful addition to a 10-gallon aquarium!

My gerbil Geronimo (rescued from the animal shelter) LOVES his new digs. He sleeps and plays downstairs and then goes upstairs for water, food, and to let me know he wants out to explore. I already had the aquarium so the tank topper made a simple addition that takes up no more floor space and gives him tons more room to climb and play. The only reason I didn't give it 5-stars is that cleaning can be kind of a pain, and he has been chewing up the plastic house...and could certainly chew up the plastic ramps too if he wanted to.