Aquaculture is the world’s fastest growing food production sector. Developing countries produce the bulk of aquaculture production, and smallholders dominate the rural landscape throughout the developing world, making up a large proportion of people involved in aquaculture production in many countries. Smallholders participate across the spectrum of aquaculture, from subsistence fish farming where aquaculture is part of a diverse household livelihood, to specialisation in more commercially oriented aquaculture, involvement in micro enterprises across value chains, and even through employment in the growing number of larger commercial aquaculture enterprises. This policy brief provides guidance on investing in the improvement of establishment of smallholder aquaculture enterprises. It builds upon experiences of working with smallholder commercial farmers in Asia, and particularly from facilitating improvements with small scale shrimp and fish farmers in Aceh, Indonesia, analyses of the Vietnamese catfish industry, a review of aquaculture producer organisations as well as cross-commodity and country comparisons. It is intended to guide both public and private actors in approaches to financing improvements in business oriented smallholder aquaculture, and to be an entry point for the private sector on more inclusive ways to engage smallholders in value chains.