Sufficient availability of good food quality is important for fish aquaculture in order to increase fish production. Microalga is one of alternative protein sources, and one among those is Chorella sp. Protein content of Chlorella sp. is very high, around 51- 58 % and consists of various kinds of essential fatty acids, which is important for fish nutrition. Recently, Algae also prospective source of ethanol biofuel. Ethanol extraction usually produce waste material, which still consist of high protein content, which valuable for fish feed sources. Therefore, the study aimed to examine the effects of fish food derived from algae biofuel-waste on growth and histological structure of wader pari (Rasbora lateristriata) intestine. Fish were divided into 5 groups of control negative (no additional protein), feed with waste algae, waste + Fresh algae, fresh algae and commercial fish food, respectively. The fish morphometry, weight, and intestine histological structure were examine. The results showed that fish feed treatment gave effect on fish growth and instestine histological structure. Algae waste feed showed similar performance to commercial fish feed on fish growth and showed no negatif effect on intestine villi length and goblet cells number, evidenced good prospect of algae waste as fish feed.

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Indonesian shortfin eel, Anguilla bicolor (McClelland, 1844) is one of fish that have swim bladder to assist swim and doing migration. Every fish has different shape, gas volume, dimension, and length ratio of swim bladder, which can play role in the difference in backscattering of acoustic energy. This study aims to determine the shape, dimensions and ratio of Anguilla bicolor’s swim bladder and their effect on target strength (TS) values. The research was conducted in two places, in the Acoustic lab, Department of Marine Science and Technology, Bogor University and Laboratory of Histology and Embryology, Faculty of Biology, Universitas Gadjah Mada. Retrieving data using the EK-15, Frequency 200 KHz tool and also the X-ray photo. The results show the shape of the swim bladder of Anguilla bicolor is elongated and consists of 1 room which is generally called a closed swim bladder. Acoustic detection results show that fish with large swim bladder volumes have large TS values and conversely fish with small swim bladder volumes have a small TS value.

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Pergerakan Ikan sidat menghasilkan suara yang disebut suara hidrodinamik yang merupakan suara atau getaran yang dihasilkan dari sebuah perubahan di medium karena pergerakan ikan. Intensitas suara hidrodinamik terjadi saat arah dan kecepatan renang ikan berubah secara cepat. Pembelokan posisi kepala akan menyebabkan perpindahan medium yang kuat.  Perpindahan tersebut menyebabkan perubahan gelombang tekanan pada medium, yang dapat terdeteksi sebagai suara oleh hydrophone. Penelitian ini bertujuan untuk menganalisis perbedaan suara ikan sidat fase elver dan fase yellow dalam kondisi terkontrol. Penelitian dilakukan di Laboratorium histologi dan embriologi Fakultas Biologi, Universitas Gadjah Mada. Waktu penelitiannya adalah 4-7 Agustus 2016. Alat yang digunakan dalam penelitian ini adalah aquarium kaca, headphone, hidrophone, Seaphone, baterai alkaline kotak, laptop. Bahan yang digunakan masing-masing 5 ekor sidat fase yellow dan fase elver.  Hasil penelitian menunjukkan bahwa Aktifitas ikan sidat fase elver dan fase yellow sangat beragam ditinjau dari  durasi suara ikan sidat saat pagi,siang dan malam.  Pola suara yang terekam berkisar dari frekuensi dari 0 sampai 22.03 KHz. Frekuensi suara ikan sidat dominan dikisaran 151 - 450 Hz, dan memiliki pola suara yang berbeda-beda untuk pagi, siang dan sore. Kesimpulan menunjukkan bahwa durasi dan pola suara hidrodinamika ikan  sidat fase elver maupun fase yellow berbeda nyata antara pagi - siang, juga siang – sore, namun untuk pagi - sore tidak berbeda nyata.