Fish with Lump

Question
Hi, I have a very large irridescent shark that I have had for years and 2 small ones. My tank is 55 gallons. The irridescents have always been very jumpy and I have had to replace broken heaters, thermometers, etc.  in the past because the shark has smashed into them. I noticed that the large shark had a large bump on the top of him between his head and top fin. It was white and almost had a cauliflower look to it. Now, it has split from 1 large bump to almost 4 smaller growths. You can still see white, but one of them almost has a brownish/red tint to it. Do you know what this could be? A tumor or an injury that got infected? The other fish are fine and he seems fine besides the growths. Thank you for any help!

Answer
Hi Alison;

It may be Lymphocystis. It is a viral infection that causes "cauliflower-looking" tumors. It isn't fatal, and the tumors often come and go, depending on the stress level of the fish. It is contagious if the fish are injured and it enters open wounds from the infected fish. Keeping the tank very clean and eating a healthy diet helps avoid outbreaks.

Here is a link to a little about it and a photo of an affected fish;

http://www.aquariumpharm.com/disease/lymphocystis.html
http://www.koivet.com/html/articles/articles_details.php?article_id=65
http://www.fishprofiles.com/articles/general/lymphocystis.asp

Let me know if this doesn't seem to be the right diagnosis once you see the pictures....

At Your Service;
Chris Robbins