Iridescent sharks

Question
QUESTION: i have a 25 cm iridescent shark which has sort of tumors at
its fins near the body and its tail is rotting.i have
separated it at once i saw this and put it in a 10 gallon
tank what should i do to help it recover and what kind of
disease is it

ANSWER: Hi Arun;

Can you get a picture of it and send it to me as an attachment to a followup question? It's hard to know what's wrong without actually seeing it. Also tell me more about your main tank; it's other inhabitants, how long it's been set up, how often you change water, how much water is changed every time, what kind of filter, water chemistry readings (pH, nitrite, ammonia, nitrate), and anything else that might seem important.  

With symptoms of tail rot my first thought is a problem with water quality or nipping by other fish. Keep the hospital tank water VERY clean and see if he improves on his own. Change out 50% of the water every day. Sometimes it's enough as it will boost the immune system of the fish so he can heal.

At Your Service;
Chris Robbins



---------- FOLLOW-UP ----------

QUESTION: i have a main tank (16gallon) full of 8 other such ones and
nothing else. i have these sharks for about 2 years. i
tried to separate them into 2 different tanks of 16 gallon
each but they did not like to be separated as they didn't
eat so i put them together that night itself. i do partial
water changing once in a week. the filter is submerged
mechanical with carbon and sponge filters.the tiny tumors
have now become red and it doesn't seem to be eating
anything. i am sorry i can't send a photo of it as i don't
have a memory card reader. i will explain the signs once
again. it seems to have red tumors/blisters over its fins
just near where they get attached to the body and half of
its tail seem to be rotting. thank you for your advice

Answer
Hi Arun;

Iridescents grow to be over 3 feet long and are a very hyperactive and nervous fish. Yours should be in at least a 55 gallon by now, and eventually in a 150 gallon. In my opinion they should not be sold in fish stores at all. Especially since most fish stores don't tell their customers the truth about these guys. Or, the fish store people don't know either. (Shame on them!) Iridescents do need to be in groups because they are a schooling catfish. Not actually a shark at all, but people like to think they have sharks as pets so that's what they are often called. ;-)

His only hope is to be in a much larger tank really. Iridescents grow to be over 3 feet long. Even though your care has been very good, a 16 gallon tank is just far too small for them and I think he's starting to show symptoms of the lack of space. He may not get better until he's in a larger tank I'm afraid. When fish outgrow their homes they often begin to deteriorate in health and die much younger than they should. Their immune systems easily collapse and they just can't stay healthy anymore. Imagine living in a small closet all your life with no opportunity to stretch your legs and move around to exercise or get enough fresh air. You wouldn't be very healthy at all. It's true for animals too.

You may have heard the myth that "fish only grow to the size of their tank". It's simply not true. They may indeed slow down in growth and die far short of their life span. Or worse, The fish continues to grow, becoming deformed and/or bending to allow swimming in their space. I once saw a koi fish like that. Koi fish grow to be over 3 feet long and can live to be over 50 years old. This one was raised in a little ten gallon tank. As he grew larger over time his spine bent sideways so he could still kind of swim at what his size would have been, about 2 feet long. It was a hideous picture that I will never forget. Please don't let that happen to your fish. If you can't get a bigger tank yourself please find someone who does that will take care of them.

Here are some web pages to support what I'm trying to say;

http://answers.yahoo.com/question/index?qid=20090313054036AA2RO9T

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

http://hubpages.com/hub/Aquarium-Giants-Which-Fish-Get-HUGE

I hope you can get them to a bigger tank soon...

At Your Service;
Chris Robbins