SIR,--Your correspondent "C. C. C." in _Land and Water_ of last week disagrees with the constant and free use of earth, which I had advocated in my article on fish culture which appeared the preceding week.

Naturally one must admit that earth at the bottom of a pond is not so great an element of beauty as is clean gravel, but the advantages are so many, that beauty must give way to usefulness. Besides this, "C. C. C."

must know that it is almost impossible to keep the gravel clean enough to look pretty, when the water is inhabited by a large number of little fish which are being constantly fed. I cannot at all agree with his advice that "earth should be avoided, or only used when necessity dictates." I believe that one of the first principles of success in fish culture is always to prevent any disease or mishap, rather than to wait for, and then try to remedy it. Trout in their natural surroundings get a dose of earth every time that there is a spate. It is very evident that the earth contains some ingredients which are not only beneficial but almost a necessity to the fish.

I have never heard of earth as an actual cure for "fungus" and should hardly think that it is active enough. There is, however, no doubt that it is one of the best preventatives to "fungus," for if it is properly and freely used it stops all chance of any decomposing material being exposed to the action of the water, and laying the fish open to the chance of a great many evils.

If suitable earth is used once a week, and even oftener on occasions, it can do no harm, and will keep the fish safe from a great many risks besides doing them very material good. I do not of course mean that the usual weekly dose should be a large one, as this would fill up the pond before the end of the season, but that a small dose should be given generally, and a large dose occasionally. I am quite sure, too, that clean earth with some nice weeds growing in it, looks better than gravel which is dirty. Gravel shows the dirt so much, that it is almost impossible to keep it looking nice where there are many fish, and it also gives the water free access to any decomposing matter.

I have never come across a case of disease caused by the use of earth, and should like to hear the details of "C. C. C.'s" experiences with regard to this matter.

CHARLES WALKER.