Littering continues to present a threat to natural environments as it may abruptly change the structure of habitats. Water bodies are among those habitats that receive most of the plastic residues that we generate. We now have a broad knowledge of how small, micro, and nano plastics affect the physiology and behavior of animals. However, larger pieces of waste may also alter behavior, interactions between animals, and interactions of animals with their environments. Here, we tested the impact of two common forms of plastic bags (floating and sinking; in pieces or in one sheet) on zebrafish behavior. Additionally, we used two different group sizes to test if the form of plastic affects differently a bigger or a smaller group of fish. We predicted that the treatment (plastic presentation and position) would affect how fast fish groups approached food, group cohesion, and space use. We found that larger groups were bolder than smaller groups, approaching food more quickly. In addition, fish were bolder when plastic bags were present, especially when the bags were near the surface of the water, creating a potential cover. Our experiment will provide the base to start exploring the effects that larger wastes could have on animals.