Nutritional damage such as scoliosis, caved-in stomach, pale colours, apathy and vulnerability to diseases are the most frequent consequences of improper nutrition. Not all fish are omnivores (eat everything). It is therefore important for fish keepers to inform themselves about the eating habits of their tank inhabitants. Herbivores such as e.g. livebearers have a digestive system that is suited for processing plant raw materials. If these fish only receive food consisting of meat only, they start developing digestion problems which progress to a vulnerability to diseases. Plecos are always wrongly assumed to be herbivores (plant eating). This, though, is not always correct. There are species that are omnivorous, or even purely carnivorous (meat eating). In the case of cichlids, for example, it is known that Tropheus species from Lake Tanganyika can't tolerate any red mosquito larvae even though they like to eat mosquito larvae.