This investigation studied the application of the effluent from co-digestion of pig manure and spent mushroom substrate as fertilizer for leaf mustard planting and as feed for Tilapia fish growing. The fish raising experiment was setting-up in 1 × 1 × 1 m hapa conditions (triplicate for each treatment) with the density of 10 invidiual per hapa; the fish weight and length were measured every ten days for 50 continuous days. The leaf mustard was planting in real conditions at the farmer’s garden with normal cultivation style, the plant weight and length were measured four times through the growing period. The study results showed that the harvest yield of leaf mustard fertilized was 5.4 times higher compared to inorganic fertilizer. In addition to its contribution to a higher yield, the effluent can accelerate the flower formation and shorten cultivation duration. For Tilapia fish culture, the growing rate of fish in the treatments supplied with 50% bio-slurry + 50% commercial food were not significantly different in comparison to fish cultivation with 100% commercial food. The results strongly confirm that the effluent from a co-digestion biogas plant of pig dung and spent mushroom compost is possible to use as organic fertilizers for not only vegetable planting but also fish culture.