Clown suddenly dies

[xbuttons]

Hi i am new to salt water tanks. I have had fresh waters tanks though. I started my first micro salt water tank about 3 months ago. i cycled the water, added some rock and then added some black juvenile clowns. I had them for about a month but they didnt pair up and started harassing each other so i took them back and my lfs replaced them without a problem. I now have had 2 new clowns for a bout 6 weeks and they have been doing really well. I have done water changes regularly and always check the water and temp. I was due for a water change tomorrow but salt and heat levels are still fine.
So here is my drama. Today i went to feed them and one was missing. I located him at the back of the tank lieing sidways breathing very heavy. I left him for a bit and tried to look up some possible problems. I went back about 15 mins later and he had died.
Yesterday he was fine and the small clown is still fine and doesnt seem to have any problems. Any clue to what might have happened? I had a bit of algae build up on the window but not to bad. Also had added some rocks i had in a fresh water tank but had boiled them and soaked them before that was done and they were put in at least 4 weeks ago.
sorry bout the long post, new and just want to know if there is anything i have done wrong so the other one doesnt die.. thanks

 

[beth]

Hello, and welcome to Saltwaterfish.com and to the hobby!
No way to really tell about this without any symptoms prior to death, or harassing activity. Just keep your eye out for brooklynella, which is a common clownfish ailment. Its a parasite, that kills rather quickly upon the onset of symptoms. Symptoms include swollen/red gills, rapid gilling, white film covering the body which may start pealing.
https://forums.saltwaterfish.com/t/127010/diseased-fish-pictures#post_914673

 

[subielover]

What are your water parameters?