Fish Q&A Section: Changes In Color
One part of my fish has turned black and there is swelling
underneath the area.
A: Sounds like a Melanocarcinoma
(tumor), that has pinched off the color controlling nerves of the
Treatment: No suitable
treatment known. Sacrifice this fish humanely.
The fish has a hazy white covering over it. It looks like a
fungus, but anti-fungal treatments do not work.
A: This is a called Columnaris Disease
and is caused by gram-negative bacteria.
Sulfa 4 TMP -or-
Triple Sulfa Powder.
My fish's colors have become very light and they seem to be under
A: Try checking your water parameters with
a test kit. This condition could be from an improper pH, or
poor water quality (Ammonia & Nitrites). Added any medications
to the tank lately? Or water conditioners? Also check to
see if something toxic is in the tank (rocks etc.)
Treatment: Do some partial
water changes and make sure you are using activated charcoal in your
filtration. Adjust pH with Sodium Monophosphate if it is too high. If the Ammonia is
high, do a partial water change, increase the aeration and use some
I have Discus.
They have all turned black and are sitting on the bottom.
A: This could be many different
things. Discus commonly turn dark when they are sick, or if
your water quality is poor. Discus are very susceptible to
protozoan diseases such as Hexamita and Chilodonella.
Treatment: If your water
quality checks out ok, and your pH is 6.5, try treating the fish
Metronidazole for 8-10 days.
I have a Koi pond, and some of the bodies of my white Koi have
turned bright red.
A: Your fish are affected by Bacterial
in the feed at 2 teaspoons per pound of food. Feed this to the
fish once a day for 10-14 days.
have some african cichlids that used to be black with white dots on
them. Their colors look strange now. I have used
medications on them but nothing has worked, any suggestions?.
A: Sounds like you have the species
"Tropheus Duboisi". The Tropheus species will change color as
they grow from juvenile species to adults. This is completely
normal and no medications are necessary.