The freshwater macroalga Oedogonium intermedium can meet the nutritional requirements of the herbivorous fish Ancistrus cirrhosus

The macroalga Oedogonium intermedium has a diverse elemental profile, high energy potential, high lipid content, a high proportion of essential amino acids and a total concentration of protein with the potential to meet the nutritional requirements of herbivorous fishes. The aim of this study was to assess growth, condition, colouration and reproductive output in an herbivorous ornamental fish. The catfish Ancistrus cirrhosus was fed one of three pelletised experimental feeds, Oedogonium, a formulated commercial feed and a 50:50 mix of the two, over a 10 month trial. After 10 months, fish that were fed exclusively on Oedogonium had equivalent growth rates, body condition, colouration, fecundity and fertilisation rates compared to those fed the commercial and mixed feeds. The absence of any major differences of these characteristics between feeds, especially between Oedogonium and the commercial feed, demonstrates the viability of Oedogonium as a feed, or significant feed ingredient, for this herbivorous fish. As such, linking the cultivation of Oedogonium with the production of herbivorous fish may provide an ideal application for Oedogonium.