UV sterilizer to help fight clownfish disease?

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Aquarium Advice Activist
Mar 20, 2012
I am concerned that my clownfish may have been exposed to clownfish disease as I had one die last week...and it appears that was the cause.

I just added a 18w UV sterilizer into the system. Do you think this could help minimize risk to my other clown?

Quick run down on the equipment in the tank.

25 gallon cube

AIO in the back has a protein skimmer, 18w UV with a 325gph power head and a maxi-jet 600 as a return.

In tank I have two Koralia 425's

There is a ton of flow, however it doesn't seem like it is too much the way it is all set up..

Water Params...
Ammonia between 0 and 0.25ppm
Nitrite 0ppm
Nitrate 5.0ppm
Temp 79.0

I know that unfortunately this clown could get it..but I am hoping the addition of a huge UV will help minimize the risk.

Why do you have any ammonia? That would worry me as well as the disease.....

AS to the question, no I dont believe the UV will help with brooklynella, I dont think its a parasite type thing like ich which can die if exposed to the UV light.
The ammonia has to be from the PJ cardinal I found dead this afternoon..he was a hider so I didn't think twice until I found him dead.
Don't expect the uv sterilizer to solve your problem all on its own. .You are going to need a more pro active treatment method.
The uv would definitely kill the parasites that flow through it.
Maybe...maybe not. With UV Sterilizers, it's all about flow rates, dwell time, and turnover rate. If the water doesn't spend enough time exposed to the proper level of UV-C, and if all the water is not flowing through the system at a high enough rate, then it will not be effective.

Although many UV Sterilizers can be effective at eradicating free-flowing algae in the water column; to control parasites requires much higher dwell time (I.E. lower flow rates) than does algae control. Based on what I've found, even those units that may be effective at bacterial control (Level 1 sterilization) do not accomplish effective parasite control (Level 2 sterilization). The bulk of the lower-end UV Sterilizers (sub-$50) are incapable of any level of sterilization and should be considered for water clarifying purposes only.

For your purposes, an 18W sterilizer connected to a 325 gph power head is at the high end of flow for even algae control. It is likely that it will be entirely ineffective for germicidal purposes.
I would be focusing on getting that ammonia down. This is what is killing your fish. The cardinal didn't die of old age.
Check ammonia this morning and it was back to 0ppm.. Nitrates were back to less than 5ppm. I think the ammonia spike was from the PJ sitting in the tank while I was at work..it is always at 0.

The UV is in the AIO and while it has high flow..the way it is angled into the 3rd chamber it isn't pushing that 325gph back into the display..it is circulating a bit in the AIO before returning. The clown seems fine..very active still and no sign of any spots.

Should I wait a few more days and do a fresh water dip?
Woke up this morning to a bunch of white spots on my clown so I did a FW dip.. He is acting lethargic, everything I saw on this said that may happen.

Any other options? I don't want to kill my fire shrimp and softies
Something in the tank is stressing your fish to death. If you find out what this is, the fish will have an excellent chance of healing up on their own. If not, you are just going to keep flushing dead fish.
Well today I lost the clownish.

At this point I only have a fire shrimp and a scooter blenny...neither are showing any symptoms of anything. As well as snails and crabs.

Am I ok with them for a while or will my tank be affected by lack of fish. I have a few mushrooms and a toadstool. Whatever the issue was I want to make sure it goes away...
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