pectoral fin injury

Question
Hello I have had my 4 fantail fish for over a week now, did everything to the book with regards to setting up the tank, etc.  Water tests and partial water changes.
However, my redcap Oranga is now very lethargic, does not eat so therefore, thought he had constipation but I have now noticed that he seems to have an injured pectoral fin, he tends to just float in the middle of the tank and just uses one fin.
He had a lice on his tail a few days ago which I removed as per instructed by my pet shop and added salt to the tank. I have added stresseze also. All the other fish are active and well. Is he injured, stressed or is it something else?
Please help
Many thanks

Answer
Hi Karen;

Are the other fish bullying him? They may need to be separated. Could there be more fish lice in that spot near the fin? Take a very close look just to be sure. You will have to watch for those little devils in the future in case there were youngsters you couldn't see.

Since the tank is new, it is going through the break-in period too. Some fish react to it more seriously than others and he may just be the first to exhibit symptoms. The others may do so very soon as well. The break-in takes about 6 weeks so you are just getting started. Keep testing the water for the levels of ammonia and nitrite. They will tell you when it's time to change some water to keep it safe for them. Here is my own web page about break-in to help you and your fish through it;

http://www.xanga.com/Expert_Fish_Help

You didn't mention what size tank your fish are in. Goldfish are very messy guys that get very large. Each one needs at least ten gallons and good filtration from a power filter that hangs on the tank or from a canister filter that hooks up with hoses. Here is a good web page about goldfish and more about what they need;

http://www.firsttankguide.net/goldfish.php

Good luck and I hope they do okay...

At Your Service;
Chris Robbins