lready exist, or
have recently existed, in fair numbers, re-stock with these fish, for
they can hardly be bettered in our waters. There are, however, some
sluggish rivers where brown trout do not thrive when they are
introduced. In such rivers and in many ponds in the South of England I
believe that no better fish exists than the rainbow trout. I say
particularly in the south, because I do not think that the rainbow trout
will ever really thrive and breed in cold waters. I have at other times
given numerous examples which go to show that the rainbow will only
thrive in warm waters.[1] I will therefore only quote the case of New
Zealand. The rainbow trout was introduced into both islands, but while
it thrived amazingly in the warm waters of the North Island, it has
proved a comparative failure in the cold waters of the South Island.

[1] _The Rainbow Trout._ Lawrence & Bullen, London.

While the common or brown trout (_Salmo fario_) and the rainbow trout
(_Salmo irideus_) are, in my opinion, to be strongly encouraged in the
waters suitable to their respective qualities, the American brook trout
(_Salvelinus fontinalis_) does not seem to have met with the approval of
most of the authorities on pisciculture in this country. My experience
of this fish is not sufficient for my holding any very strong views with
regard to its suitability to British waters. In one case I know that it
was a great success for two seasons, but I have not had any opportunity
of following it up in this particular instance. In another case it was a
decided failure. I am sure that it should not be introduced into streams
where brown trout thrive, and I am doubtful of its ever succeeding in
waters which are suitable to the rainbow trout.

Of all the trout, the rainbow is the hardiest, and the one with which
the amateur pisciculturist is most likely to be successful. It is also
the fish most likely to supply a want felt by very many fishermen, a
good sporting fish in waters where the common trout will not thrive.

In large and deep ponds with a good stream, or in lakes, char may be
tried with a prospect of success. They require cold waters, and I have
never heard of their being successfully introduced in the South of
England. They are a more difficult fish to rear than trout.

Grayling have many violent opponents, but I am inclined to think that
they do but little if any harm in a trout stream, and they supply
excellent fishing during part of the c