white scum on fish

Question
hi there, i just recently bought more fish,gold fantails and black redfin sharks, i also have a big id shark that ive had for over a year, now my big shark has white scum over its eyes and the gold fish are getting a white scum on therir sides,do you know what this is or what i should do about it?  thanks joanne

Answer
Hi Joanne;

There are several possibilities. It could be an infection of some kind, toxins have spiked from the addition of new fish and are irritating them, or your redfin sharks are bullying them. You didn't mention what size tank they are in and what size all the fish are but redfins need lots of space, are very territorial and can be pretty nasty. Make a 25% water change and very carefully watch the redfins from a distance. They like to stake out territory and defend it fiercely, especially from their own kind. You really should only have one redfin per tank. Your others could even be hitting themselves on things and causing themselves injury from fleeing the redfins.

Have the water tested for the levels of pH, ammonia, nitrite and nitrate too. If any are elevated, that's probably what is irritating them. Make a 25% water change right away and again every day that toxins are elevated. Then make 25% changes once a week every week along with gravel vacuuming to keep wastes low. Every tank needs weekly changing.

Gold Fantails are a fancy goldfish and really should never be with tropicals, especially redfin sharks. I would take them back to the store or get them their own coldwater tank. Here is a web page about tank size and caring for goldfish;

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

At Your Service;
Chris Robbins