OPEN ACCESS International Journal of Aquatic Science ISSN: 2008-8019 Vol. 6, No. 2, 39-47, 2015 () sulistiyarto@gmail.com Colonization by Bloodworms (Chironomidae Larvae) using Artificial Substrates in Floodplain Waters: Effect of Exposure Periods and Season Bambang Sulistiyarto 1 and Ivone Christiana 2 1) Fisheries Faculty, Palangka Raya Christian University, Indonesia 2) Agricultural Faculty, Palangka Raya University, Indonesia Received: 03 March 2015 Accepted: 05 June 2015 Published: 06 June 2015 Abstract: Chironomidae larvae or bloodworms are natural food that has the nutrients suitable for freshwater fish needs. This study aims to determine the effect of exposure periods of artificial substrates and season on increase of bloodworms biomass. The highest quantity of bloodworms biomass in artificial substrates was obtained during the exposure periods of 14-21 days in March (high water phase). Bloodworms biomass were positively correlated with water quality parameters such as nitrate (r = 0.848), orthophosphate (r = 0.805) and pH (r = 0.662) whereas negatively correlated with total suspended solid (r = - 0.642). Bloodworm production capacity in floodplain waters reached 1.934 tons dry-weight.ha -1 .yr -1 . The production of bloodworms in floodplain waters using artificial substrate can support the availability of natural food for fish farming. Key words: bloodworm, floodplain, macroinvertebrate, natural fish food Introduction Macroinvertebrates in freshwater are dominated by dipteran larvae (Wetzel, 2001). Chironomidae are flying insects included in the order Diptera and frequently, are the most abundant taxa found in this water bodies. At larval stage, Chironomidae are aquatic macro- invertebrates that live predominantly at the bottom of freshwater, such as rivers, lakes, marshes and ponds. Approximately 93% of macroinvertebrates community in peat swamp waters of Central Kalimantan Indonesia is dominated by Chironomidae larvae (Wulandari et al., 2005). Floodplain is the aquatic ecosystem marginal to the river and created by main channel’s runoff (Welcomme, 1983). In floodplains, Chiro- nomidae larvae can be found in abundance throughout the year (Sulistiyarto, 2011), due to the high availability of food in these environments, especially organic detritus (De Haas et al., 2006; Solomon et al., 2008). Deposits of organic matter in floodplain are