I think that in the case of a bare water, a year at least should be devoted to developing a good supply of vegetation. This will generally produce a considerable amount of animal life, without any artificial help, but judicious help will be sure to accelerate matters to a considerable extent. I would, however, advise the amateur not to attempt to introduce a quantity of creatures into his water, until the vegetable life therein is well established. For instance, though fresh-water snails are desirable in every trout water, if introduced in large numbers into a water in which the vegetation is small and not well established, they will eat down the weeds too much and then die off from disease caused by want of sufficient nourishment. Having established the vegetable life well in a water, and developed it to a considerable extent, the amateur may begin to examine his water, and find out how much animal life exists there, and to stock with creatures suitable for food, according to what he finds in the water. Fresh-water snails are always desirable. In streams, or in ponds with streams running into them, the fresh-water shrimps (_Gammarus pulex_) should always be tried. It does not do in some waters, but where it does thrive it increases very rapidly, and forms about the best article of food that can be given to trout. _Corixae_, which thrive in ponds and sluggish waters, should always be introduced. They increase rapidly, and are taken by most fish, particularly by trout. The amateur should be careful when he introduces these creatures to make sure that he is putting in the right creature. The water-boatman (_Nautonecta glauca_) is a member of the same family, but is no use as food for the fish. He swims on his back, is longer and narrower than are _Corixae_, which do not swim on their backs, are smaller, broader, and live much more under water than the water-boatman. It is generally advisable to avoid water-beetles, as most of them are more likely to do harm than good, such a number of our water-beetles being carnivorous. They will probably not harm adult fish, but they will destroy ova and fry. I have known a _Dytiscus marginalis_ kill a trout of nearly a quarter of a pound in weight.