be given to the fry as soon as they
are old enough to manage them. _Corixae_ and other small insects should
also be given as often as possible. The fresh-water shrimp is bred in
running water, _Corixae_ in still or slow running water. Weeds are
necessary to the well-being of both.

The boxes must be kept carefully covered, as I have already pointed out.
A kingfisher would make short work of a box of fry, and other birds and
beasts of various kinds are partial to them. There are only two courses
open to the fish culturist in dealing with these enemies--to protect his
fish or kill the enemies. I prefer to protect the fish first and kill
the enemies afterwards.

The greatest care must be taken not to introduce, or allow to intrude,
any water beetles or the larger carnivorous aquatic larvae of insects,
into the rearing boxes. I have known cases where the larvae of the
_Dytiscus marginalis_, the largest of our carnivorous water beetles,
have destroyed almost all the fry in a rearing pond. The adult _D.
marginalis_ itself is not a whit less voracious, and much stronger than
its larva.

If the wooden parts of the apparatus have been properly prepared,
according to my previous instructions, there should be no risk of the
fry developing fungus. Quite a small spot of woodwork, however, left
uncovered by asphalt-varnish, or enamel, or uncharred, will render the
chance of the development of this disease probable.

Should by any misfortune fungus get into the rearing boxes, a dose of
salt may very likely cure it. Sea water is the best, but if this is not
obtainable, a solution of salt and water run through the boxes will
probably cure the disease. Considerable good may also be done to the
young fish by occasionally putting a lump of rock salt in at the inlet,
and the water allowed to run over and dissolve it.

CHAPTER VIII

TROUT. THE MANAGEMENT OF THE FRY (_Continued_)

In the last chapter I brought my reader up to the point where the fry,
which had been feeding for some time in the rearing boxes, had been
judiciously separated, the weaker and smaller fish which took up their
positions at the lower ends of the boxes having been put into separate
boxes and induced as much as possible to keep at the head near to where
the current enters.

It is difficult to lay down any certain rule as to what is the best time
at which to take the next step--that of turning the fry out into the
rearing ponds. When the fry have got