AbstractIntroductionMarine microalgae protein has better solubility and digestibility than other protein‐based feeds. Apart from protein, high‐value biomolecules have an immense potential to enhance the quality of feed, but knowledge about them is scarce.ObjectiveMarine microalga Picochlorum sp. biomass molecular characterisation along with commonly used protein feed such as fishmeal and soymeal for potential feed ingredients.MethodologyLiquid chromatography coupled with mass spectrometry (LC–MS) was used for biomolecular characterisation. The correlation of biomolecules sets was evaluated using principal component analysis (PCA) and heatmap clustering.ResultsLC–MS identified 116 biomolecules cumulatively among microalga, fishmeal, and soymeal that includes fatty acids, acylglycerols, vitamins, sterols, pigments, nucleotides, unique amino acids, amines, sugars and miscellaneous. These 116 biomolecules were screened based on their functional importance as feed ingredients. Among the different sets of biomolecules, microalga contained a more diverse set of fatty acids, pigments, sterols, and vitamins than acylglycerols, unique amino acids, nucleotides, and sugars. Fishmeal contained a more diverse set of acylglycerols, unique amino acids, nucleotides, and amines, while soymeal contained the highest number of sugars and miscellaneous biomolecules. The PCA confirmed the significance level (P > 95%) and heatmap clustering showed the diversity and relatedness of biomolecules among the microalga, fishmeal, and soymeal.ConclusionThis study showed that the marine microalga Picochlorum sp. biomass has a rich source of biomolecules and could complement fishmeal or soymeal in feed and is also sustainable and economical as compared to fishmeal and soymeal.