Tujuan Penelitian Ini Adalah Untuk Melihat Pengaruh Pemberian Hormon Tiroksin Dengan Teknik Yang Berbeda Terhadap Pertumbuhan Dan Kelangsungan Hidup Larva Ikan Lele Dumbo (Clarias Sp.). Penelitian Ini Dimulai Pada Bulan Oktober - November Di Laboratorium Mini Hetchery, Fakultas Perikanan Dan Ilmu Kelautan, Universitas Borneo Tarakan. Menggunakan Metode Rancangan Acak Lengkap (RAL), Terdiri Dari 4 Taraf Perlakuan Dan 5 Ulangan. Perlakuan 1 Pemberian Tiroksin Melalui Perendaman, Perlakuan 2 Melalui Pakan Alami Moina Sp. Perlakuan 3 Melalui Perendaman Larva Dan Pakan Alami Moina Sp. (Perlakuan Kombinasi P1 + P2), Dan Kontrol Tanpa Tiroksin. Dosis Hormon Tiroksin Diberikan Sebanyak 0,05 Ppm Dan Pemberian Hormon Tiroksin Hanya Diawal Penelitian Dengan Frekuensi Pemberian Satu Kali Di Awal Penelitian. Parameter Yang Diukur Adalah Pertumbuhan Berat Mutlak (Growth Rate/GR), Pertumbuhan Berat Harian (Spesifik Growth Rate/SGR), Tingkat Kelangsungan Hidup (Survival Rate/SR) Dan Kualitas Air. Hasil Analisis Sidik Ragam Menunjukkan Perlakuan Yang Diberikan Tidak Memberikan Hasil Yang Berbeda Nyata Terhadap Nilai GR, SGR, SR Pada Larva Ikan Lele Dumbo (Clarias Sp.) Yang Diujikan. Data Kualitas Air Selama Penelitian Menunjukkan Suhu Berkisar Antara 26,3 – 29,9°C, Oksigen Terlarut (DO) Berkisar Antara 3,54 – 4,26 Ppm, PH 6,65 – 7,89 Dan Amoniak 0,594 – 2,380 Ppm. Kesimpulan Penelitian Bahwa Pemberian Hormon Tiroksin Pada Larva Ikan Lele Dumbo (Clarias Sp.) Dengan Teknik Yang Berbeda Tidak Memberikan Pengaruh Berbeda Nyata.
Kata Kunci: Hormon Tiroksin, Kelangsungan Hidup, Larva Ikan Lele Dumbo (Clarias Sp.), Pertumbuhan

The Purpose Of This Study Was To Examine The Effect Of Thyroxine Hormone Administration With Different Techniques On The Growth And Survival Of African Catfish Larvae (Clarias Sp.). This Research Began In October - November At The Mini Hetchery Laboratory, Faculty Of Fisheries And Marine Sciences, University Of Borneo Tarakan. Using A Completely Randomized Design Method (CRD), Consisting Of 4 Treatment Levels And 5 Replications. Treatment 1 Administration Of Thyroxine Through Immersion, Treatment 2 Through Natural Feed Moina Sp. Treatment 3 Through Immersion Of Larvae And Natural Feed Moina Sp. (Combination Treatment P1 + P2), And Control Without Thyroxine. Thyroxine Hormone Dose Was Given As Much As 0.05 Ppm And Thyroxine Hormone Administration Was Only At The Beginning Of The Study With The Frequency Of One-Time Administration At The Beginning Of The Study. Parameters Measured Were Growth In Absolute Weight (Growth Rate / GR), Daily Weight Growth (Specific Growth Rate / SGR), Survival Rate (Survival Rate / SR) And Water Quality. The Results Of The Analysis Of Variance Showed The Treatment Given Did Not Give Results That Were Significantly Different From The GR, SGR, SR Values In The Larvae Of Catfish (Clarias Sp.) Tested. Water Quality Data During The Study Showed Temperatures Ranging From 26.3 - 29.9 ° C, Dissolved Oxygen (DO) Ranging From 3.54 - 4.26 Ppm, PH 6.65 - 7.89 And Ammonia 0.594 - 2.380 Ppm. The Conclusion Of The Study Is That The Administration Of Thyroxine Hormone In The African Catfish Larvae (Clarias Sp.) With Different Techniques Did Not Have A Significantly Different Effect. Keywords: Growth, Larvae Of African Catfish (Clarias Sp.), Survival, Thyroxine Hormone