Black spots and dead fish

Question
QUESTION: Hi, we have had a 55 gal saltwater tank, for 10 years with little to no problems.  Recently we lost 5 tangs to what we thought was a anemone spliting and giving off some type of poison.  The clown fish survived and a week latter they started showing black spots.  The clowns are otherwise healthy and eating.  We took advantage of the loss and replaced our sand,glass tank, and lighting system with new.  All chem levels are testing spot on in the tank and yet the clowns still have these black spots 3 weeks latter. I have read the the  zoas could be stinging them.  Is it possible that the zoanthids could be the problem after all?
Thanks

ANSWER: Hi Amy,

Thank you for the question.

I am sorry to hear of your misfortune.

It's highly unlikely that your zoanthid corals are causing any issues for your clownfish. Clownfish are immune to stinging cnidae called nematocysts, that anemones and many other corals are armed with, including zoanthid. These cnidae are used by the corals to sting and capture microscopic organisms like copepods, to consume as food items. The clownfish uses this stinging sensation as therapy, and it also helps to keep the clownfish free of certain parasites. In turn typically the clownfish will help keep the host coral fed, and will ward off any intruders that may normally harm the coral.

In fact, my Percula Clownfish loves his large colony of orange zoanthid corals, and hardly ever leaves them, other than to eat.

Without seeing your fish, but from what you described, perhaps your fish have what is called Black Spot (Diplopstomiasis)

Below, I have included a link, with extended detailed information, regarding Black Spot

http://www.fishdeals.com/fish_diseases/black_spot/

P.S. Since you mentioned that you just replaced the sand, and set it back up again, I highly recommend to add a beneficial bacteria to your aquarium, like Brightwell Aquatics MicroBacter7, which will help jump start your aquariums natural biological processes.

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

QUESTION: Hi Thanks for the respond. Since my posting my question. We had the levels in the tank all tested (all spot on)and the corals were growing/spreading like crazy so we decided to add two fish.  Not Good! They both DIED! They did some very strange behavior stuff like trying to escape from the top.  Swimming very erratic and crazy. They were in the tank about 16 - 20 hours. Both of our original clowns are still alive and fine, the black spots are getting better. The clowns aren't rubbing against anything or showing any signs of distress. We didn't do anything to the sump or bio balls so we thought that the bacteria levels would be fine. We did replace the protein skimmer bulb. Could something be in the bio balls? How would I test these?  I don't want to start over! We have taken water samples to various shops and we have been told they can't find anything. The tank was tested for copper and it showed none. I'm at the point of shutting it all down after 10 years and calling it quits.

ANSWER: Amy,

My recommendation is to not add any new fish to your aquarium; at least not at this time.

I also recommend to add a liquid beneficial bacteria, (like MicroBacter 7) to help boost your aquariums existing bacteria, which will also help to boost your aquariums existing biological filtration.

For all new future fish additions, make sure you quarantine them first, for at least a few weeks, before adding them to your main show tank.

I also recommend to test your water parameters yourself, versus bringing them to a pet store like Petco; typically pet store personnel are not knowledgeable and trained enough, to accurately and correctly test your water parameters. Of course, your local aquarium fish store, that you've shopped at for years, that you know and trust, would be the exception.

Regards,
Dave



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

QUESTION: Problem solved.  Cleaned out Bio balls and found MANY pieces of the anemone in the balls.  We rinsed cleaned, full water change,cleaned sump and we are up and running.  Added a new damsel next day and 4 days latter a yellow tang all is well and tank is amazing again! Corals are huge and bright, fish are eating and happy. Our local store is a fish supply only store that has been here for at least 15 years very knowledgeable and helpful. He came out to the house and helped us find the problem. I don't believe we will ever put an anemone in our tank again.

Answer
Hi Amy,

I am glad to hear that you found the problem, and I'm also glad to hear that you didn't give up!

Regarding your bio-balls, if you have a sump / wet-dry filter that has a built-in tray area (above the bio-balls), to hold filter floss, make use of it. The filter floss will filter out and catch most debris and large particulates, before it has a chance to get tangled up and settled inside your bio-balls. It's recommended to change the filter floss, at least once a week. You may want to also increase the water flow through your bio-balls, this will also help to dislodge anything that may get trapped in or around your bio-balls. Lastly you may want to remove just a couple of your bio-balls, so that you don't have too many, to the point where they are packed inside of your sump / wet-dry filter compartment.

Happy Fish Keeping!

Regards,
Dave

All Experts Editor

http://www.ocreef.com - Director