Abstract :
This research was carried out for 14 days in April 2019 at the Fish Seed Center (BBI) Faculty of Agriculture, Riau Islamic University, Pekanbaru. This study aims to determine the optimal dose of mahogany leaf extract solution for the treatment of Saprolegnia sp. Fungal infections in carp (Cyprinus carpio) seeds. The method used was an experimental method using a Completely Randomized Design (CRD) with 5 treatments and 3 replications, namely: (P1) 0.4 gr / l, (P2) 0.5 gr / l, (P3) 0.6 gr / l , (P4) 0.7 gr / l, and (P5) 0.8 gr / l water. The test fish used were 1-month-old carp seeds with a length of ± 3.5 cm and a weight of ± 1.20 gr / head obtained from the nursery of Mr. Markam Jalan Kesehatan, Pekanbaru City, Riau Province. The container used is 80 liters of aquarium capacity of 15 pieces. The results were obtained, the lowest infected fish of Saprolegnia sp was in treatment (P5) as many as 3.33%, and the highest in treatment (P1) was 46.67%. The highest percentage of survival was found in treatment (P2) which was 76.67%, and the lowest in treatment (P5) was 20.00%. Water quality parameters are good enough for test fish, the results of water quality measurements in this study are Temperature 25-28ºC, pH 7, Dissolved Oxygen from 3.43 to 5.53 mg / l and Ammonia from 0.07 to 0.53 mg / l.