<p class="abstrak">This study aims to determine the optimal stocking density of tiger shrimp seed (Penaeus monodon) were maintained in media biofloc. This study uses a randomized complete design with four treatments and three replications ie, treatment A control (10 tiger shrimp seed / container without the addition bioflok), treatment B (10 tiger shrimp seed / container with the addition bioflok), treatment C (15 tiger shrimp seed / container with the addition bioflok) , treatment D (tiger shrimp seed / container with the addition bioflok). The observed parameters include the specific growth rate (SGR), a daily increase of the absolute length and survival rate (SR) and feed efficiency. The results showed that the stocking density gives significantly effect to increase the daily increase of the absolute length, SGR and feed efficiency value of tiger prawn seed. Values length and SGR growth are highest in treatment C respectively, 3.1 ± 0.06 cm and 1.48 ± 0.041%/day, meanwhile, the value of feed efficiency is highest in treatment D amounted to 47,43 ± 7,26%. There is no significant effect between the stocking density differences of each treatment on the survival of tiger shrimp juvenile Optimal maintenance toward stocking density for tiger shrimp seed using bioflok system is 15 tiger shrimp seed / 10 liters of water.</p><p class="abstrak">Penelitian ini bertujuan menentukan padat tebar optimal benih udang windu (Penaeus monodon) yang dipelihara dalam media bioflok. Penelitian ini menggunakan rancangan acak lengkap dengan empat perlakuan dan tiga ulangan yaitu, perlakuan A kontrol (10 ekor/wadah tanpa penambahan bioflok), perlakuan B (10 ekor/wadah dengan penambahan bioflok), perlakuan C (15 ekor/wadah dengan penambahan bioflok), perlakuan D (20 ekor/wadah dengan penambahan bioflok). Parameter yang diamati meliputi kelangsungan hidup (SR), Pertambahan Panjang Mutlak, Laju Pertumbuhan Spesifik (SGR) dan Efisiensi Pakan. Hasil penelitian menunjukkan bahwa perbedaan padat tebar berpengaruh nyata meningkatkan pertumbuhan panjang, SGR dan nilai efisiensi pakan benih udang windu. Nilai pertumbuhan panjang dan SGR tertinggi terdapat pada perlakuan C masing masing sebesar 3,1±0,06 cm dan 1,48±0,041%/hari, sedangkan nilai efesiensi pakan tertinggi terdapat pada perlakuan D sebesar 47,43±7,62%. Tidak terdapat perbedaan yang nyata antara perbedaaan padat tebar tiap perlakuan terhadap kelangsungan hidup benih udah windu. Padat tebar optimal pemeliharaan benih udang windu dengan menggunakan sistem bioflok adalah 15 ekor/ 10 liter air.</p>