The introduction of non-native fish can lead to the predation of the native fish fauna or competition for food. There is also the risk of disease being introduced, which can further threaten native populations. In some cases, the introduced species can disturb the environment so much that it becomes unsuitable for particular fish. For example, a major problem has been found with ruffe. This non-native fish has now been introduced into a number of lakes in recent years. It is known that ruffe eat the eggs of vendace, which are particularly vulnerable because of their long incubation period. This means that they are susceptible to predators for up to 120 days. The eggs of other fish, for example roach, are only at risk for as little as three days.