by Midge Hill
Until discovering this method of treating tail rot, I had previously
run into one problem or another with any other medhod of treatment I
tried...either the medication did little or nothing to cure the tail
rot, or it worked fine on the tail rot but damaged the health of the
Having gone through a wide variety of formulas to cure the bain of the
guppy breeder I gradually reached the conclusion that anything that was
strong enough to cure the tail rotbefore the show value of the guppy
was lost, was too strong for the guppy to live in safely.
The answer had to lie in getting a super strong dose on the tail area
without giving the guppy the same dosage. Since this theory obviously
does away with adding medication to the tank water, the next locical
step was to net the guppy out of the water for treatment.
To make a long story short, several methods and several types of medication
were tried. The easiest and most effective method turned out to be as follows:
All signs of tail rot should be gone by the next day and within a week new growth
should be visible. Ocassionally a fish needs more than one treatment (maybe a spot was
missed during the first treatment). Because the functional part of the guppy
does not come in contact with the medication it has proven perfectly safe to
repeat the treatment as often as necessary to clear up even the most persistant
- Net the fish and hold it in the net until the first wild
thrashing aroung stops.
- Hold the fish firmly but gently within the net so his head
is uphill from his tail... this is vital as thestrong medication
must not run down in to the gill areas. Should this happen,
immediately return the fish to the tank and cross your fingers.
- Paint the exposed side of the guppy tail, beginning at the
peduncle and concentrating on ther final fringe where the tail
rot is most active.
- Paint the other side of the tail right through the net from
- Wait about 20 seconds after painting then return the fish to
his home tank (providing of course, that it is clean and well cared for).
The medication that has proven most effective on my guppies is Tetra care
Fungistop (active ingredients: colloidal silver, natrium chloratum, Ma-gn.sulphuric)
used full strength from the bottle painting directly on the tail it seems to
stop the tail rot ‘right now’ and regrowth begins quickly... no need to trim
away diseased areas. If the tail rot has not been allowed to progress very far, the
fish is back in show finnage in no time at all. And since it is not necessary to
add medication to the tank water, the fish is not weakened but remains hardy and
vigorous. It has certainly proven to be the quickest, safest method I have
A Note from Luke Roebuck
Midge's article is excellent, and the procedure and principle remain sound today.
I have had greater success, however, with a different medication while using the
I have had success using MERCUROCHROME in lieu of Fungistop. It is easily
obtainable at most drugstores. The application and principle remain the same,
but I have found that immediately after the 20 second wait from medicating, the
addition of a few drops of Kordon’s Novaqua to the fish's entire body area, including
the treated area, will effectively act as a "band-aid". It will help prevent further
infection, and aid in healing damage caused to the slime coat by the medication
and by subsequent stress, or accidental dosage to the gill area.
When the tail rot has progressed into more than 5% of the caudal area, I recommend
caudal surgery to ensure complete destruction and removal of the diseased tissue.
This is best achieved with a new scalpel, a 3" x 5" index card, and a flat-based
container in which to place the card and perform the surgery. The card must be new,
clean, and wetted in a concentrated solution of Mechurochrome and salt. The fish is
laid flat on the card in the container, and the tail spread with a clean, small,
The diseased area of the tail should be cut sharply with the scalpel by pressing
down and away from the fish, making sure to penetrate through the index card. The
newly cut area should then be painted with the Mecurochrome solution as mentioned
above, and followed shortly afterwards with the application of Novaqua. The freshly
cut edge seems to induce the fish to release blood clotting hormones and antibodies
which accelerate the healing and regrowth process more rapidly than it would to an
uncut diseased tail edge.
To ensure that the fish doesn't jump off the operating table, I recommend covering
the fish with the net lightly, just enough to hinder movement without damage to the
guppy. The guppy can be returned to his tank soon after treatment. A clean tank is
even better as the pathogen load will be much less during the healing period.