Black Moor - tail blister

Question
I have had my ten gallon tank for about two months.  It has one 2 year old black
moor in it.  The filter is an aquaclear 3.0.  I have recently changed about half of
the water.  I just noticed that my beautiful fish has a blister (one blister) at the
base of his tail on the fin not the body.  

What is it ? and is it deadly?

Answer
Hi Douglas;

It may be nothing at all but watch to see if it changes. Sometimes fish injure themselves and get bruised or scraped. Especially during a water change. We can't always see every move they make so it happens sometimes without us knowing what happened. Melafix and aquarium salt are good things to keep around at times like this. They help avoid infection and help heal tissues. Follow the instructions on the labels.

If it looks like a tiny white salt speck, it's "ick", which is a parasite. You can get medicine for it at the local fish store. Do it right away so it doesn't spread.

At Your Service;
Chris Robbins