The great plague and bane of fish in moats, great and small, and other little standing waters, are great and sharp frosts. I have used all the tricks that I have heard of, which are not a few, or could devise, to save my fish in such waters; and yet in ten years time I have lost three or four thousand carps. But yet I have found ways to save the life of many a fair carp, when my neighbours have lost all; which I shall declare as my own experience, and may be profitable upon like occasions to any that will use them. First, as to the sorts of fish that suffer most, I can only say, that the tench, if any, is frost-proof, and will shift in extremity; but if the frost be intense and long, the other sorts, as carps, eels, pike, perch, and roach, will go near to perish; and I have found not any great difference of hardness, but when one fish complains, they are all in imminent danger. The waters most obnoxious to frosts are such as are standing, shallow, or small. For if there be either a water-current, or a fresh spring, no fish dies for frost. If an hard winter succeeds a very dry summer, the fish suffers most. If the ponds are large and deep, such as I have directed to be made upon the channel of water, which may not run but upon floods or rain, the fish will never die in frost there; but such waters you must look upon as the asylum for the securing the fish in extremity; and all that you can put in there alive, though through a hole in the ice, will certainly live. If the bank of a pond sews, it will preserve the fish in frost; the reason, as I imagine, is, because where the water sews out, the air will bubble in, which relieves the fish; or perhaps it might put the water into some degree of motion. If so, the stirring water with a board flat upon a pole put under the ice, might do good; but this is conjecture. The symptom of mortality to your fish in time of frost, is, their shewing themselves; which if you perceive in the least, conclude all are going; and without a thaw, that water will not keep them alive. For it is the nature of fish in cold weather to lie as close and deep as they can; so that nothing but the pangs of death shall make them move. If no holes are broke, they will rise and stick to the ice, and be frozen to it; if there be holes, they will move about them, as if they came up for fresh air. When the frost hath continued long, and hard, that you begin to suspect your fish, you may make a trial by cutting holes in several places, some in the middle, and some by the sides of the waters that are obnoxious; that is, after about ten days freezing; and by the appearing of the fish, or not, you shall discover the temper and condition they are in; therefore watch them diligently. If they are not well, they will appear; then prepare all hands to take out every fish, as near as you can; for what you take out, you may preserve, and all that are left behind, are probably lost.