Fish Q&A Section:  Changes In Color


Q:  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 fish

Treatment:  No suitable treatment known.  Sacrifice this fish humanely.

Q:  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.

Treatment:  Use TMP-Sulfa -or- Sulfa 4 TMP -or- Triple Sulfa Powder.

Q:  My fish's colors have become very light and they seem to be under stress.

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 Aqua Gold.

Q:  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 with some Metronidazole for 8-10 days.

Q:  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 Hemorrhagic Septicemia. 

Treatment:  Use Oxytetracycline in the feed at 2 teaspoons per pound of food.  Feed this to the fish once a day for 10-14 days.

Q: I 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.



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