WATER QUALITY IMPROVEMENT AND ANALYSIS FOR CLOWN FISH (Amphiprion ocellaris) CULTIVATION IN A RECIRCULATION SYSTEM

The demand for ornamental fish is currently increasing while the availability in nature decreasing due to overfishing. Clownfish (Amphiprion ocellaris) a type of marine that widely kept aquariums, but problem rapid decline water quality activity these fish. recirculation system one way can be used management. study aimed analyze filter stabilize seawater clownfish (rearing containers. This research was conducted from January April 2021 at Research Centre Sibolga Fisheries College. method an experimental using one-factor Completely Randomized Design (CRD) with four treatment levels and three replications. treatments this were P0 (unfiltered), P1 (cotton filter), P2 (fiber P3 (activated charcoal filter). 2 – 3 cm size, aquarium measuring 60x40x40cm stocking density fish/L fed tubifex times day, 08.00 18.00 WIB as much 5% their body weight. Parameters measured temperature, pH, DO, salinity, ammonia, phosphate, abundance bacteria, phytoplankton, survival clownfish. Water measurements are carried out every 7 days. results obtained improvement analysis cultivation provide influence on rearing container. temperature 27.9–28.0 0C, pH 8.3–8.4, DO 7.5–8.0 mg/L, salinity 33-34 ppt, ammonia 0.04–0.06 phosphate 0.47–0.48 mg/L bacterial 2.35x104 CFU/mL rate 95.55%.