Tetra's StartZyme combines all the benefits of a complete water conditioner to make your water immediately safe for tropical fish, Goldfish, and marine fish. Instantly neutralizes harmful chlorine, chloramines and heavy metals to make tap water safe. Stimulates the natural protective slime coat to reduce stress and help fish heal wounds. Start Zyme also contains a safe blend of bacteria and enzymes to help establish the biological cycle and break down organic sludge to ensure a healthy and clean aquarium. The easy-to-use fizz tablets come 8 to a package.