This unique packaging consists of nitrogen flushed foil bags for maximum freshness and will be placed in our super seal bottles with colorful new labels This nitro pack will maintain the soft and moist characteristics that are distinctive to Ocean Nutrition: fresh seafood, increased palatability, and easy digestion In addition, the Formula One and Two Marine Pellets also contain garlic, to aid in disease resistance, krill, for color enhancing, and HUFA#039;s The distinguishing nitro pack guarantees at least a one year of shelf freshness (23 months once nitro pack is opened), ensuring your fish get our finest, freshest product Formula One is red and larger amounts of krill like our frozen and flake products, it is produced with higher protein levels Formula Two is green and is for fish with lower protein needs The food contains less krill, but much more Spirulina, kelp, and other natural algae The pellet sizes are small for feeding fish from one inch long, and medium, for feeding fish four inches long