clown death

So I did a "fish" cycle with Dr Tim's One and Only and a maroon clown in a 36gal bow. First week went fine, small spike in ammonia, followed by an increase in 'trites. Ph always around 7.9-8.0. Have a skimmer running (started after 48 hours of using O&O) in a sump. For the last week, the ammonia has been at 0, the 'trites have gone down to 0 as of friday night, the ph around 8, and 'trates around 5.0, sg at 1.025 as of friday night. The clown had been eating every night, including Friday night, and was very active. I was at the end of my cycle, so I thought, until I got home yesterday from work. I found my clown at the bottom of the tank, breathing heavy. I moved him to the sump where he later died. I did a test and my parameters were as follows, SG = 1.025, Ammonia = 0, Nitrites = <.25, Nitrates = around 5.0, temp = 76*.
I have done nothing different, still have the same 2 Koralia 425s, same skimmer running, still same light schedule, everything... Can't understand what happened and why something didn't happen before now.
Totally discouraged and I just finished my cycle....

 

Sorry.

There are a few diseases that can kill Clownfish quickly. Regardless of a small ammonia spike, ammonia burns gills leaving any fish more compromised.

As long as you saw no physical symptoms of disease typical with Clowns like Brookynella and Marine Ich or Ammylodinium, it is would probably safe to add another Clownfish once the cycle is complete.

If you are still showing detectable Nitrites your cycle is not complete.

Good Luck.

 

No physical signs of any disease. Looked the same for the entire 2 weeks. Ate well every day and moved about the tank constantly. I was gone to work yesterday from 9am (the lights weren't on yet) until 5pm, when I noticed the problem. No spots, sores, erosion, or damage of any kind on the body.
I was under the impression that I shouldn't do a water change until I was cycled. I guess I should do one now. Would a 20% be about right?
I am scared of adding another fish right now.
I am noticing some algae and am wondering if I could introduce s CUC in yet.

 

You can do a water change and add the a small CUC if you only have a little algae.

You're going to get tons of different views or opinions on how to cycle a tank.

IMO a soft cycle with water changes to keep ammonia and nitrite level in check is an acceptable way to cycle but tad harder to do with your first tank.

To be safe I do think that adding live stock only after the initial cycle when there is no detectable ammonia and nitrite is safe and effective way to cycle a tank.

After you add live stock, do not over feed and do the appropriate water change based on the values of ammonia, nitrite and nitrates.