Bull minnows are omnivores and feed on whatever is available, including crustaceans (grass shrimp, various small crabs, isopods, amphipods etc.), insects and worms (annelids and polychaetes). Young fish are said to be detritivores but readily consume live foods in aquaria.

Omnivores (from Latin: omne all, everything; vorare to devour) are species that eat both plants and animals as their primary food source. They are opportunistic, general feeders not specifically adapted to eat and digest either meat or plant material exclusively

Detritivores, also known as detritus feeders or saprophages, are heterotrophs that obtain nutrients by consuming detritus (decomposing organic matter).^[1] By doing so, they contribute to decomposition and the nutrient cycles.

Hell I didn' know so I had to look those two words up.