Fin rot found in fish
Fin rot is a symptom of disease in fish; it is not hard to treat,
and the fish usually will survive. Most common in the fancy
varieties of goldfish and
Bettas, fin rot can occur as a result
of an injury, as a secondary infection once the fish has been
weakened by another disease, or in some cases, as a primary
infection (bacterial).
Fin rot can be the result of a bacterial infection (which causes
a more ragged rotting), or as a fungal infection (which rots the
tail more evenly and is more likely to produce a white 'edge').
Sometimes, both types of infection are seen together. Infection
is commonly brought on by bad water conditions, injury, poor
diet, or outside wintering fancy goldfish (who should live in warmer
temperatures).
Fin rot starts at the edge of the fins, and destroys more and
more tissue until it reaches the fin base. If it does reach the
fin base, the fish will never be able to regenerate the lost
tissue. At this point, the disease may attack the fish's body
directly.
Treatments for fin rot
Fungus: For fish large enough to handle, catch the fish, and dab
malachite green directly on the fungus with a Q-tip. This is
extremely effective. Repeat treatments may be necessary.
Bacterial: Antibiotic treatment in a quarantine tank. This is
stressful for the fish, and doesn't always work, so be sure of
what you are doing before you attempt it. If the fish is still
eating, the best bet is an antibiotic food. Tetra makes one that
works well -- just buy the one for bacterial diseases and follow
the directions on the can.
Fin Rot Prevention
With very few exceptions, virtually all cases are precipitated by
stress, fear or poor environmental conditions.