Abstract

 Gut contents of the hard-lipped barb (Osteochilus hasselti (Valenciennes, 1842)) and the tiny scale barb (Thynnichthys thynnoides (Bleeker, 1852)) were analyzed.  Fish samples were collected from Kaeng Lawa, Khon Kaen Province, northeastern Thailand during the hot season (April and May 2009) and the late rainy season (September 2009).  The percentage of frequency of occurrences (%F) and percentage of proportions (%P) of food items were evaluated.  O. hasselti consumed 11 food items, only 7 categories were found in both seasons which consisted of detritus (66.67%, 42.00%P), plant parts (21.34%, 35.00%P), algae (4.00%, 9.00%P), unidentified items (5.34%, 4.00%P), protozoa (1.06%, 2.00%P), aquatic insect fragments (0.53%, 2.00%P) and diatoms (1.06%, 0.30%P), respectively.  Whereas, T. thynnoides consumed 7 food items and only 5 food catergories were found in both seasons consisting of detritus (87.36%, 70.00%P), rotifers (7.37%, 6.00%P), unidentified items (2.11%, 3.00%P), plant parts (2.11%, 1.00%P) and aquatic insect fragments (1.05%, 3.00%P).  From Chi-Square test for independence, it was found that %P of food items depended on season and fish species (p < 0.05).  The result of present study, it was concluded that O. hasselti and T. thynnoides are omnivores.

Key words: Gut content, Osteochilus hasselti, Thynnichthys thynnoides, Kaeng Lawa, northeastern Thailand.