Page 324 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

322 POND FISH: ILLNESS AND TREATMENT

Health concerns No signs of erosion; fins not
clamped against the body
Fins should not
appear bloodshot
Flanks are clear
of red, inflamed
Regular pond maintenance and water-quality checks areas
help keep diseases away from fish, but illnesses still
occur, even in the best-kept ponds. The first sign of
a problem may be a fish floating at the surface, by No unusual
attachments
which time it is probably too late for effective Gills not flared, on the body
with regular
treatment. For this reason, it is vital to set up a routine movements visible Belly not
bloated
for examining fish; feeding time provides an ideal A healthy fish appears active and feeds well. This Fantail
Goldfish (Carassius auratus) demonstrates what to look
opportunity to check their appearance and behavior. in a well-kept specimen.

Environmental problems Dealing with disease
The health of pond fish is hugely influenced by environmental Disease-causing bacteria, fungi, and parasites may be
conditions. During spells of hot weather, for example, introduced into the pond whenever it is stocked with fish or
evaporation can significantly lower water levels, which has plants. Undesirable organisms can also be brought in on the
the effect of concentrating dissolved nitrogenous waste. At bodies of animals, especially wading birds, that move from
the same time, elevated temperatures drive oxygen out of the pond to pond. These can multiply and cause serious harm
water; the combination of nitrate and oxygen stress can be
fatal, especially for larger fish. Many of these problems can be Bloat, or dropsy, is a serious
avoided simply by topping off water levels regularly during the condition, often caused by a
summer and incorporating a pump and filter; these improve fungal or bacterial infection.
water quality, break down waste, and increase oxygen content Isolate affected fish as a
precaution, but this does
by creating water movement. Overstocking a pond, especially not normally prove highly
if it is not well established, places great stress on its occupants, infectious.
and fish may succumb to usually benign bacteria that are
present naturally in the water. Overfeeding is another
common environmental problem, especially in temperate Fin rot begins in the inter-fin
areas in the spring and fall; uneaten food decomposes ray membranes but spreads
in the water, encouraging populations of pathogens. down the fins until it reaches
the body, when it can be fatal.
In extreme cases, rotten parts
Fish lice can resemble small of fins may need to be cut off
patches of green algae on under anesthesia.
the body of a fish

Fish lice are crustacean parasites that Dying or dead fish will often float to
feed on fish blood. They are obvious the surface of the pond. If not spotted or
when attached to the body but also live attended to quickly, they are likely to be
free in the water for up to two weeks. taken by bird or animal scavengers.

US_322-325_Illness_Breeding_Ch.indd 322 29/08/18 4:11 PM