Sick Celestrial

Question
100l tank about 5 months old.
2 Shibunkins, 1 lion head, 2 fan tail, 2 goldfish and the sick Celestrial.

The Celestrial is very sick. The fish is starting to turn black on the fins and remaining on the bottom of the tank. The fish was eating well until today. Unfortunatly the poor thing seems to be breathing very fast too.

I am unable to test the water quality at present. But all other fish in the tank are doing fine.

I preform water changes once a week removing 30l of water whilst vacuming the gravel.  

Answer
Hi Craig;

I apologize for not answering you sooner. The AllExperts system wouldn't let me answer my questions yesterday.

I hope he is still alive......

The black indicates burns from toxins. It is most likely because the tank is overcrowded and ammonia and/or nitrite has spiked from it. Make an immediate water change of 25% and do the same every day until the fish is feeling better. Also add aquarium salt or any uniodized pure salt. The dosage is 1/2 teaspoon per gallon of water and add more only after replacing water. But, only add enough to treat the replaced water. This way the salt concentration remains the same. Your tank is about 25 gallons, but you will have to convert this formula to metric I guess. Sorry, but I'm in the USA and don't have a conversion chart handy. I just wanted to get to you as quickly as possible to help your poor fish. The salt with help the sick one breathe better and prevent infection.

The tank really should only have a total of 3 or 4 goldfish in it. They get big, 6 to 8 inches, and are deep-bodied messy fellas. Provide plenty of air with an air pump and airstone to help them out in the meantime. Also avoid overfeeding.

Not every fish is affected as seriously by toxins at first. The celestial, being a weaker variety, was affected more easily. Unless the fish is new and the exposure to toxins happened at the place he came from? The move would certainly have stressed him out. The black is actually scabs from burns healing, so the danger may be past and he is experienceing the after effects. Or, did you change the filter media lately? That can cause toxins to rise also until the beneficial bacteria get going in the new media. Let me know what you think about all that so we can hopefully prevent the others from getting sick.

Followups welcome

At Your Service;
Chris Robbins

Come on over and join us on the freshwater fish forum at About.com to get even more information too;
http://freshaquarium.about.com/od/questionsanswers/a/naavigateforum.htm

My member name is ChrisR62. See You There!