Toys “R” Us has become the latest retailer to agree to stop selling the miniature aquarium, Planet Frog. Biologists, wildlife specialists, and PETA have warned that aquariums such as Planet Frog, which houses two frogs in crowded conditions, are too small and inhumane. Confining the energetic animals to cramped spaces can slowly poison the creatures by their own waste.

Target, JCPenney, Rite Aid, Walgreens, and Albertsons have also discontinued sales of the tanks.