Furan 2 dip

I had been seeing these ulcer looking wounds on the sides of the Zoanthid polyps and was trying to find out what was causing it and what could be done to stop it. The rock went through a course of fresh water dips in an attempt to rid the Zoanthid's of their infliction with no results. This photo was taken 02-22-2008.

I had to start wearing glasses about 5 years ago cause I can't focus on things really well up close. So I have been taking photos of my tank friends with a macro lens on a Nikon D50. I started taking photos of these Zoanthids because it looked like the skirts where falling off the polyps. Well, they weren't falling off they were getting eaten off by Nudibranches! Not only were the Nudibranches eating the skirts off the polyps but they were eating the soft tissue that runs up the side of the polyps. The photo below is not that great but this is how I found the nudi's. Look at the end of the arrows on top of the closed polyp. Check out some of the polyps in the photo below and you can see the damage done to some of the polyp's skirts.

I irradiated all the nudi's from the rock by getting the rock out of the water and using a magnifying loop and pair of tweezers and physically removing every nudi I saw. The nudi's were the same color as the polyp's and this made me curious as to what kind they were. After searching quite a number of web sites I came across one that had the culprit. Berghia (Aeolidiella stephanieae) are known and being sold by quite a few web sites as being Aiptasia eaters and they may eat Aiptasia, but there were no Aiptasia in my tank. So, guess what they were eating. That's right, when there is no Aiptasia food source, they will begin to eat the Zoanthids.

This species of Nudibranch appears to be the Aeolidiopsis which is a solar-powered Nudibranch, harboring and utilizing the zooxanthellae from the cnidarians they are feeding on. The close color match between the Nudibranch and the polyps, is because in both cases the background color is caused by the symbiotic zooxanthellae taken from the Zoanthids they were feeding on. I found this to be true because one of the Nudi's had got free from this rock and was attacking a green colony of Zoanthids and that Nudi did turn green in color and it was of the same species.

Here are some links with close up photos of these critters.

Aeolid nudibranch Berghia article by Anthony Calfo

More Information, Answering Questions About Eggs and Size (Berghia net)

Buy Berghia at The salty underground

I can't believe there are actually sites that will sell you these critters!

The destruction they cause is absolutely incredible and they are very small!
Good luck on getting them out of your tank!

This photo was taken 03-23-2008.

There was a definite decline of the colonies of Zoanthids on this rock that lasted 3 weeks. It was full of polyps when I bought it. After conducting hundreds of searches on the internet and by phone to different oceanographic researchers about the possible fix for declining Zoanthids due to being eaten by Nudibranches, I was referred to a product that is used in the treatment of Zoa Pox.

The product is called Furan 2 and is produced by Aquarium Pharmaceuticals (API) as an anti-bacterial fish medication. I found several recipes for treatment on the internet and settled on using one and I started a regimen of dips with API's Furan 2.

The mixture for treatment

One packet of the Furan 2, to 3 cups of freshly prepared salt water.

I dipped the entire rock, totally submerged in a mix of 2 packets to 6 cups of saltwater for 20 minutes.

I did 3 dips, one each day back to back, then let the colony rest for four days.

The Zoa's didn't seem to have any ill effects from the dip and the healthy Zoa's had all reopened after 15 minutes or so of being back in the tank.

Active ingredients: 60 mg Nitrofurazone and 25 mg Furazolidone per pack.

Here is the rock before being dipped and as it was being dipped.

And here is what the Zoanthid colony looks like as of 6/6/2008

Here is a shot of this rock, taken on 7-25-2008.