Decomposers are consumers that obtain energy by feeding on and breaking down detritus. Detritus is the waste and remains of dead organisms. Animals that eat detritus are often called scavengers.They include earthworms, some rodents and insects, crayfish, catfish, and vultures.The main decomposers are bacteria and fungi.ecomposers are consumers that obtain energy by feeding on and breaking down detritus. Detritus is the waste and remains of dead organisms. Animals that eat detritus are often called scavengers.