ABSTRAK Penelitian “Pengaruh Pemberian Pakan Cacing Tanah Lumbricus rubellus Terhadap Warna pada Ikan Guppy Poecilia reticulata”, yang bertujuan untuk mengetahui pengaruh penambahan pakan tambahan cacing tanah Lumbricus rubellus pada pakan ikan hias guppy Poecilia reticulata terhadap perubahan warna. Penelitian ini dilakukan selama satu bulan dengan 3 perlakuan pemberian pakan yaitu W0 (pemberian tepung Ikan tanpa pemberian tepung Cacing tanah Lumbricus rubellus), W1 (tepung Cacing tanah Lumbricus rubellus dan tepung Ikan) dan W2 (tepung Cacing tanah Lumbricus rubellus). Akuarium yang disediakan sebanyak 3 unit dengan ukuran 12 cm x 20 cm x 20 cm. Ikan uji (± 3 cm), dibeli dari tempat budidaya dan di aklimatisasi selanjutnya ditabur sebanyak 3 ekor per akuarium. Pemberian pakan sebanyak 3% dari berat ikan uji dan dilakukan dua kali sehari. Parameter kualitas air yang diukur adalah suhu, pH dan oksigen terlarut (DO). Analisis data dengan rumus hendry dan grime (1993). Hasil penelitian menunjukkan bahwa terjadi eningkatan karatenoid pada ikan guppy Poecilia reticulata pada setiap perlakuan yaitu perlakuan W0, W1 dan W2, dan peningkatan karatenoid tertinggi terjadi pada perlakuan W2. Kata kunci : pakan, Poecilia reticulata, Lumbricus rubellus, perubahan warna. ABSTRACT The research “The Influence of Giving Earth-Worm Woof Lumbricus rubellus Toward Colour Alteration to The Guppy Fish Poecilia reticulata”, which aim to find the influence of earth-worm Lumbricus rubellus extra increment toward colour alteration to the guppy fish Poecilia reticulata. The research was conducted for a month by three treatment woof that were W0 (giving fish meal without earth-worm woof Lumbricus rubellus), W1 (earth-worm woof Lumbricus rubellus with fish meal), and W2 (earth-worm woof Lumbricus rubellus without fish meal). The available aquariums were 3 units with size 12cm x 20cm x 20 cm. The fish testing (± 3 cm) which were from cultivation place and they were acclimated. They were sowed to the aquarium and each aquarium has 3 fish on it. The giving woof 3% was based on the weight of the fish and it was done 2 times a day. The parameter of water quality that were be measured in this research were temperature, pH, and dissolved oxygen (DO). Data analysis with henry and grime formula (1993). The result of the research showed that there was increasing of caratenoid to the guppy fish Poecilia reticulata in each treatment based on the treatment in W0, W1 and W2. The high carotenoid increasing occur in W2. Keywords: woof, Poecilia reticulata, Lumbricus rebellus, colour alteration