Ive brought a new goldfish and now my others are turning red why?

Question

the tails are all red and the bodys are starting to change red, one of them is not eatting and is not swimming around. the new fish is fine, iv tested the water is it is perfect someone please help me.

Answer 1

Define "perfect", because many times, my definition of perfect (0 ppm ammonia and nitrite, and less than 20 ppm nitrate) is very different than the askers'.  If you've got any traces of ammonia, you're probably seeing ammonia burns on the fish.  If this is not the case, you're probably seeing septicemia, which is a bacterial infection common in tanks with poor water quality.  Regardless of the cause, more frequent water changes will help, but if it's septicemia, you will also need to remove any activated carbon from the filter, then treat with Maracyn TC, Maracyn 2, Furan 2, Triple Sulfa, Trisulfa, Metronidazole, Flagyl, Hexamit, Kanaplex, or Terramycin.

Septicemia: http://www.biotech-weblog.com/50226711/i...

http://www.healthnews-stat.com/primages/...

http://home.nps.gov/piro/naturescience/i...

Answer 2

nosoup4u said it all

Answer 3

The new fish must be diseased...you should have put him in quarantine for 4 weeks at least..you should always make sure the new fish is healthy before introducing it to the main tank...separate him...and for the main tank..start with some aquarium salt...and see what happens to them...hopefully the saltbath will help...research on goldfish diseases and see for any symptoms..u can get info on Koko's goldfish site...