Does hydrilla provide good habitat for fish? Initially, yes. Aquatic plants are an important part of Lake Austin's environment, providing habitat and food for organisms living there. Before it gets too dense, hydrilla can provide good habitat for fish. However, fish populations are negatively affected when hydrilla exceeds 30-40% coverage of the lake. Hydrilla will grow with less light and fewer nutrients than other aquatic plants, and can outcompete all other native and non-native plants. Eventually, decomposing plants can rob the water of oxygen needed for fish and a healthy aquatic community.