582 REPORT OF THE COMMISSIONER OF FISHERIES. 
not to undertake its culture he has the following to say on this subject 
(Prnce, (897, poo): 
German carp are especially subject to parasites and contagious diseases. From 
their omnivorous and lethargic habits no fish are so readily attacked by diseases and 
parasites as carp. The ‘‘fish leprosy,’’ described by Blake as a fungoid growth 
which spreads over the whole skin, turning the fish white and rendering it most 
unhealthy and a source of disease to all other fish, is essentially a disease of the 
German carp. Frank Buckland studied some of the diseases of these fish, and 
among others enumerated one malady which he called small-pox in the carp.¢ 
Tapeworms and other disgusting endo-parasites occur most plentifully in carp. 
One described by Harrington Keene taken from a carp of 16 pounds weight meas- 
ured no less than 45 feet in length. Of all fresh water fishes the German carp are 
the most subject to external and internal diseases. This is, in fact, unavoidable in 
a family like the carps, with sluggish habits, a fondness for coarse and loathsome 
food, and a preference for muddy and almost tepid waters. 
If any of the above is from Professor Prince’s own observations I 
feel quite certain that he can not, at all events, have made them in 
this country. And if the German carp in Europe has been found to 
be subject to a number of diseases and parasites, it must be remem- - 
bered that this is a subject upon which comparatively little is known 
in general, and that the carp, being a cultivated fish, has afforded 
opportunity for close study which most others have not. Certain it 
is that some of the fungus diseases to which he applies such awful 
names will attack almost any fish or other water animal under condi- 
tions unfavorable to the latter, and especially if there happen to be 
any abrasions of the integument. The carp’s hardiness in this respect 
is one of its chief characters, allowing of its cultivation in ponds and 
small enclosures, conditions under which many of our native fish 
would succumb to fungus and other diseases ina short time. Then, 
too, contagious diseases, strictly speaking, are, according to present 
knowledge, extremely rare among fish, and I am not aware that any 
has yet been found which attacks the carp. The whole tone of Pro- 
fessor Prince’s paper leads us to suspect that if he were studying a 
fish malady he would call it by some such name as smallpox in carp, 
whatever title he might use to designate it in other species. 
Jt remains now to consider certain enemies which menace the fish, 
especially those which may attack them while they are in the ponds. 
These are in reality very few in such ponds as are in use in this coun- 
try, since the impounded fish are all adults, and the adult carp has 
comparatively few serious natural enemies. With the young fish it is 
different, and the regular carp culturist has, of course, to deal with all 
these factors. The eggs are exposed to a great number of dangers, and 
especially are they open to the attacks of minnows and other small 
«The disease here referred to is apparently due to one of the Myxosporidia called by Hofer (1896, 
1896, 1896b) Myxobolus eyprinit. This appears to be not uncommon in European carp ponds, but Iam 
not aware of its ever haying been reported on the carp in this country. I have not had opportunity 
to examine the recent handbook of fish diseases by Hofer (1904). 
