Sera ImmunPro Nature is a slow sinking, granular, probiotic growth food for fish over 4cm long. This high-quality food supports balanced and healthy growth, strengthened immune system and is free from dyes and preservatives. Available in 112g, 440g and 4.4kg packs. Please select the required size from the drop-down menu. (Sera also offer Sera ImmunPro Mini Nature, for fish less than 4cm in length.)