coi trouble

Question
Hello Christy!

Ok So we have a 12" coi fish who has been with us for three years, He lives with six other fishes the tank is 4'Long, 18"Wide, and the height is 19". His skin is all white but today we noticed on some places on his body there are red looking spots and the scales their look veiny,but they are not bleeding just pinkish red and he looks in pain. He eats but he doesn't swim very well. Can you please help me find a way to help him or any thing we can do to get him normal again.
Thank you Melanne.

Answer
Hi Melanne
Well, I'm not a koi expert, never had them before.  But, I do know they're supposed to grow to about 3+ feet, and really should have about a 1000 gallon pond to be in.  They're really not good aquarium fish.  Your tank from those dimensions is about 70 gallons(270 Litres).  

The first thing I would suggest is to check your water quality.  Do you have a test kit that tests ammonia, nitrites, and nitrates?  If so what are those readings?  If not, I'd strongly suggesting getting one.  Your ammonia and nitrites should be reading 0 ppm, and nitrates under 20 ppm.  If there's ammonia present in the tank, it's most likely ammonia poisoning the fish is suffering from.  Do an immediate water change, and continue with daily water changes until the ammonia is gone.  

If the ammonia levels are fine, another possibility is an internal bacterial infection called septicemia.  The best treatment for this is an antibacterial food, Jungle Labs makes some.  This way it gets the medicine inside the fish where it is most effective.

Not sure what your other fish are in the tank with it, but it may be overstocked.  Make sure you're doing weekly water changes of about 30-40%.  Might even be best to do them twice a week-changing about 20% each time.  Also at least once a week be sure to vacuum the gravel/substrate well.

Hope that helps and let me know if you have more questions.

Christy