Now the next thing that I will commend to your consideration is, that
the Trout is of a more sudden growth than other fish. Concerning
which, you are also to take notice, that he lives not so long as the
Pearch, and divers other fishes do, as Sir Francis Bacon hath observed
in his History of  Life and Death.

And next you are to take notice, that he is not like the Crocodile, which
if he lives never so long, vet always thrives till his death: but 'tis not so
with the Trout; for after he is come to his full growth, he declines in his
body, and keeps his bigness, or thrives only in his head till his death.
And you are to know, that he will, about, especially before, the time of
his spawning, get, almost miraculously, through weirs and flood-gates,
against the stream; even through such high and swift places as is almost
incredible. Next, that the Trout usually spawns about October or
November, but in some rivers a little sooner or later; which is the more
observable, because most other fish spawn in the spring or summer,
when the sun hath warmed both the earth and water, and made it fit for
generation. And you are to note, that he continues many months out of
season; for it may be observed of the Trout, that he is like the Buck or
the Ox, that will not be fat in many months, though he go in the very
same pastures that horses do, which will be fat in one month: and so
you may observe, That most other fishes recover strength, and grow
sooner fat and in season than the Trout doth.

And next you are to note, That till the sun gets to such a height as to
warm the earth and the water, the Trout is sick, and lean, and lousy, and
unwholesome; for you shall, in winter, find him to have a big head, and,
then, to be lank and thin and lean; at which time many of them have
sticking on them Sugs, or Trout-lice; which is a kind of a worm, in
shape like a clove, or pin with a big head, and sticks close to him, and
sucks his moisture, those, I think, the Trout breeds himself: and never
thrives till he free himself from them, which is when warm weather
comes; and, then, as he grows stronger, he gets from the dead still water
into the sharp streams and the gravel, and, there, rubs off these worms
or lice; and then, as he grows stronger, so he gets him into swifter and
swifter streams, and there lies at the watch for any fly or minnow that
comes near to him; and he especially loves the May-fly, which is bred
of the cod-worm, or cadis; and these make the Trout bold and lusty, and
he is usually fatter and better meat at the end of that month than at any
time of the year.