The Garden Magazine, August, 1921 
359 
to reduce the number of wrigglers which hatch from those eggs, 
o so much the better for them. In due course they will all grow 
up and become lusty mosquitoes. To put kerosene on this 
water will not solve the problem, for who wants a pool of kero- 
. sene in his garden? Hence the advisability of putting in 
fishes, which in nature would be there anyway. 
; What kind of fish will best serve the purpose, especially in 
■ temperate latitudes, has never been worked out satisfactorily 
by experiment. Certain general principles of the problem may, 
however, be set forth authoritatively. Most small fishes will 
eat wrigglers, but (and here lies the first difficulty) the wriggler is 
so small that a fish of any size will not pay attention to him. 
We must, therefore, have fish as small as possible for this pur- 
pose. Full grown, ornamental goldfish are too large. 
On the other hand, the goldfish will be very useful if adults 
be put in early in the season, to lay their eggs from which a 
brood of young, sharp-sighted babies hatch. The little fellows 
would scarcely be noticed by a person standing at the edge of 
the pool because of their small size, and because they are dull 
dark olive in color, the bright golden red being only attained 
with age. They are there, none the less, an important factor in 
keeping the wrigglers in check. 
The spawning of goldfish is dependent on the water tem- 
perature. They will spawn when it has risen to between 6o° 
and 68° F., and about 68° is most favorable both for spawning 
and the development of their fry. 
Both goldfish and pearl roach are peaceful fishes, and there will 
be no trouble in keeping other smaller kinds with them even at 
close quarters. Probably the very best fishes for holding 
mosquito larvae in check will be found among the ovoviviparous 
or live-bearing members of the tooth-carp family. This is a 
statement which perhaps requires some explanation. 
All the various kinds of true minnows, as well as the goldfish 
and the large carp, are strictly fresh water fishes belonging to 
the carp family. They have no teeth in the mouth, but one or 
more rows of teeth on the bones of the throat. They abound in 
cold waters to the north. In tropical, sub-tropical, and the 
warmer temperate fresh, brackish and salt waters, small minnow- 
like fishes occur which are quite unrelated to the above. They 
are generally less active, with a tail-fin squarish or rounded 
instead of with a tendency to be forked. A forked propeller in 
aquatic creatures is an indication of extensive rapid swimming, 
which we may suppose would be impeded by any obstruction in 
the centre, where the stream-lines along the sides of a moving 
body converge. Like most true minnows these fish have a 
single non-spiny fin in the back, but it is placed nearer the tail, an 
indication of their relationship, which is really much closer, to 
the big pickerel, pike, and muskallunge. 
These little fishes, furthermore, have teeth in the jaws, and 
hence the family goes by the name of tooth-carps. Colloquially 
the various kinds are called killifish, top minnow, etc., etc. 
Some of them become exceedingly abundant, fairly swarm in 
favorable localities; as for instance the common killifish, alias 
mummy, alias salt marsh minnow, in the salt and brackish 
shallows of our Atlantic coast. 
The species of the tooth-carp family are separable into two 
groups according to their methods of reproduction. Some of 
them lay eggs like ordinary fishes; and in others, the ovovivipar- 
ous or live-bearing group, the eggs hatch and young develop 
within the body cavity of the mother, and are launched into the 
world as active and hungry young fishes of sufficient size to 
fend for themselves successfully. 
This system, wherein much waste is eliminated, makes for 
rapid multiplication of individuals. Many species of these 
live-bearing tooth-carps swarm in the fresh waters of middle 
America and the West Indies, two are abundant in the south- 
eastern United States, and one of these two, Gambusia affinis, 
extends northward along the Atlantic coast to about Delaware 
Bay. They are among the smallest fresh-water fishes; and may 
be looked for in every ditch or pool in the tropics. Doubtless 
in some cases they have been placed there for the purpose of 
holding mosquitoes in check, to which function they are so well 
Mattie Edwards Hewitt, Photo. 
THE LILYPOND AT “ROCKMARGE,” PRIDE’S CROSSING, MASS. 
Fish are indispensable in such a pool, for though we would not do without Water-lilies the accompanying mosquito must be 
reckoned with, and in this fight man’s best allies are the smaller kinds of fish which feed upon insect larvae. Bowered in the 
cool green of Rhododendrons this pool near the dwelling of Judge Wm. H. Moore irresistibly allures on hot midsummer days 
