Im a beginner aquarist

Question
Hello. I've had an aquarium 5 days ago and i added some chemicals named diamond to remove chlorine impurities. Then I added two apollo sharks the 1st day. Then i added four guppies and two apollo sharks the next day and three black sharks the next day. The third day two guppies died mysteriously and two black sharks died by developing white substance all over their body. Then i added two swordtails yesterday and my third black shark is about to die due to the same disease. Can u tell me what i should do to stop my fishes from being dead? N my tank is a 10 gallon tank n i've a filter,heater, thermometer n all the basic needs of a tank.

Answer
Hi Shashwat;

It isn't disease, your tank is just too new for so many fish so soon and too small for the types of fish you have. Waste toxins from the "break in period" are poisoning them and burning their skin, eyes, and gills. The only fish you have that are okay to keep in a ten gallon tank are the guppies. Here's why;

Apollo sharks grow to be over 8 inches long and need at least a 40 gallon tank.

Black sharks grow to be at least a foot long and need at least 70 gallon tank. They are also aggressive and not suitable for community tanks.

Swordtails grow to be about 5 inches long and need at least a 20 gallon tank.  

To hopefully keep alive what you have left, immediately make a 50% water change and make a 25% water change every day until you can decide what to do next. You may have to start over and definitely need to do some reading about new tanks and tank setup as well as fish compatibility and their needs. Here are some web pages to help you with that;

http://expert-fish-help.xanga.com/

http://freshaquarium.about.com/od/aquariumstartup/Aquarium_Startup.htm

http://freshaquarium.about.com/cs/beginnerinfo/a/fishcalc.htm

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

http://freshaquarium.about.com/od/aquariumstartup/a/newtankmistakes.htm

Good luck and I hope things get better very soon...

At Your Service;
Chris Robbins