Powerhouse Waterfish and Medaka filtration material is a porous ceramic that balances microorganisms into the inside of the filtration, creating water quality suitable for the breeding of goldfish and leda. It suppresses pH dropping and keeps the breeding water neutral to fine alkaline, so it is not only ideal for goldfish and fish, but it is also ideal for goldfish where breed water can oxidize easily. Compatible with various filters. Estimated usage fee: 11.8 inches (30 cm) aquarium: 17.7 inches (45 cm) aquarium: 1 - 2 bags