摘要：This study was conducted to examine the effect of alkalinity on survival and growth of Siam patin catfish ( Pangasius sp.). Fish larvae were reared in aquaria in density of 4 fishes per liter. Water alkalinity examined was 15 ppm CaCO 3 as control, and 25, 50, and 75 ppm CaCO 3 as treatments. During first 7 days, larvae were fed on nauplii Artemia sp. 4 times daily and continuing fed on Tubifex sp. for 23 days. The results of study showed that higher survival rate was obtained in treatment 50 ppm CaCO 3 (94.16%). Higher daily growth rate was also achieved by that treatment. Keywords: Siam patin catfish, Pangasius , Alkalinity, CaCO 3 ABSTRAK Penelitian ini bertujuan untuk mengetahui pengaruh alkalinitas terhadap kelangsungan hidup dan pertumbuhan larva ikan patin Siam ( Pangasius sp.). Larva ikan patin dipelihara dalam akuarium dengan kepadatan 4 ekor/L. Alkalinitas air yang digunakan adalah 15 ppm CaCO 3 sebagai kontrol, dan perlakuan 25, 50 serta 75 ppm CaCO 3 . Selama 7 hari pertama, pakan yang diberikan berupa naupli A rtemia sp. setiap 4 jam sekali dan diteruskan dengan cacing sutera ( Tubifex sp.) selama 23 hari. Hasil penelitian menunjukkan bahwa kelangsungan hidup larva tertinggi diperoleh pada perlakuan alkalinitas 50 ppm CaCO 3 (94,16%). Laju pertumbuhan harian tertinggi juga diperoleh pada perlakuan alkalinitas 50 ppm CaCO 3 (6,65%). Kata kunci: ikan patin Siam, Pangasius , Alkalinitas dan CaCO 3
