Aquatic Plant Forum banner

UV Sterilizers/Fish Diseases

21168 Views 59 Replies 17 Participants Last post by  dwalstad
Here's an e-mail question that I just received. I thought this question deserved its own folder and a public answer.

mpe1329 said:
Sorry to bother you, but I read with interest your advice re fish TB and UV sterilizers. My experience has been that SW fish are hard to kill and FW fish hard to keep alive, which seemed counter-intuitive to me until I read your posts. May I ask what type/brand of UV sterilizer you use? Any recommendations about the wattage of the bulb would also be appreciated.

My Response:

During the MB (mycobacteriosis) outbreak two years ago I used two different brands of UV sterilizers. They were the 'UV Gamma 'and the 'Turbo-twist' with either 8 or 9 watt bulbs for my 45, 50, and 55 gal tanks. One sterilizer for each tank. The UV sterilizers stopped the disease in its tracks and saved my fish.

While the above filters worked wonders, they were hard for me to hook up to the biofilters I use. You see, these particular UV filters are really just a container that directs water in a spiral path around the UV lamp. You have to pump water through them from a separate apparatus.

Recently, an experienced hobbyist on this forum highly recommended the Submariner UV sterilizer. This filter combines the UV and biofilter into one apparatus. I just bought one ($80) and am going to set it up for my 50 gal tank. It has a 7 watt UV lamp. I'm going to use this tank as a quarantine tank for new fish.

Folks, many fish being sold are carrying diseases. UV sterilizers will kill not only bacteria but many parasites (e.g. Ich). UV sterilization is being increasingly used in wastewater treatment. Recently, wastewater treatment scientists showed that UV light is highly effective in killing Giardia cysts, a human parasite. My reasoning: if UV sterilization kills human parasites and their cysts, it will probably kill fish parasites and their cysts. I think SW (saltwater) hobbyists are ahead of us on this.

One minor caveat for UV sterilizers.... UV sterilizers can interfere with iron uptake by non-rooted plants (UV light oxidizes the iron chelators). Thus, you may need to add some chelated iron if your plants show iron deficiencies. However, I had no problems with iron deficiency when I used the UV sterilizers in my NPT tanks.

Below is a website that has more information on brands of UV sterilizers:
  • Like
Reactions: 1
1 - 13 of 60 Posts
oh, ps.. Any studies on its effectiveness with certain algae?
Any UV sterilizer will kill green water algae. If it doesn't, there's something wrong with the UV lamp (too old), or its quartz glass housing needs to be cleaned.

The UV lamp zapps algae cells as the water passes through the filter. UV sterilizers are a mainstay for pond hobbyists to kill green water algae. It will not kill attached algae (hair and blue-green algae) for the simple reason that these algae don't pass through the filter.

Folks, UV light has a common killing mechanism for all cells. It kills by damaging RNA and DNA, two essential components of all living cells. Thus, UV light will kill many of the microorganisms, viruses, small parasites, and green-water algae that pass through the filter.

Newly purchased fish are often:

  • carrying disease organisms they've picked up along the way from fishfarm, fish wholesalers, aquarium store, etc
  • have not yet developed immunity to the microorganisms (natural flora) in your tank
  • severely stressed by transport

A UV sterilizer severely reduces the number of potential pathogens, so that the new fish has a chance to develop its immunity and fight off disease.
See less See more
Amen, Brother!

The transmission of mycobacteriosis from aquarium fish to humans is relatively rare but can happen. The result is painful, slow-healing (2-12 months) sores on hands and arms.

One hobbyist in my aquarium society recently had a sliver on her finger that got infected after cleaning her tanks. The hobbyist's doctor was going to surgically remove the painful sore that just wouldn't go away. Just by chance, another hobbyist suggested it might be "Fish Tank Syndrome" and to check with a fish veterinarian. Sure enough, it was from the fish tanks! The doctor then put the hobbyist on the right antibiotics to heal the sore. Ironically, none of her fish appeared to be diseased.

Folks, a UV sterilizer will certainly help. In the meantime, wash your hands and arms soon (within 30 min) after cleaning tanks. If you have an open wound or are immuno-compromised, take extra precautions.
See less See more
Thanks for this thread!

How long should you use it in a TB infected tank? Indefinitely or when the fish have stopped succumbing? I made a post in your diseased fish thread. I don't know if you've read it but my endlers have it. They've stopped dying for now but a female is getting pretty big so, I check to make sure her tail isn't withering away. I know it'll never go away but am just wondering whether I should always use the UV and add some iron or not? The original inhabitants stopped dying and so, I thought they were healthy. They obviously weren't and had spread the disease while appearing in perfect health.

Just saw your post today.

I kept the UV sterilizer on 24 hr a day for about 4 months. A couple fish that were too far gone died, but a couple got better. Then... no more started showing symptoms. After awhile, the fish looked so good that I removed the UV sterilizers entirely from the 3 tanks.

The vet that diagnosed my fish also found that they had an Aeromonas infection as well as the TB (mycobacteriosis). Aeromonas is another bacteria that probably attacks fish weakened by TB (the two bacteria are frequently found together in diseased fish).

My experience suggests that all is not lost even if you do have diseased fish in your tank. A UV sterilizer will block transmission from one fish to the other. It will also reduce the fish's exposure to secondary pathogens (like the Aeromonas). Healthy fish can fight off small numbers of potential pathogens (Ich, TB, Aeromonas, etc) that are a natural part of their environment. A UV sterilizer could reduce the total potential pathogen population down to numbers a healthy fish (or maybe even a stressed fish) could handle.
See less See more
Here's an excellent question from Aquabillers regarding the UV thread:

"I thought the idea of the NPT approach was to simplify things. From the thread on UV filtering, it seems to make things more complicated.

Knock on wood, my fish don't get sick..."

I guess an NPT is anything you want it to be. I'm personally "fed up" dealing with diseases from fish I've purchased. I admit that I have been extremely negligent in not using a quarantine tank for new fish. But those carefree days are over!

My reason for promoting quarantine tanks and UV sterilizers: Too many hobbyists (with or without NPTs) get discouraged and quit the hobby when their fish become diseased and die. [And, I really would like to continue selling more books!]

The risk of disease when introducing new fish is enormous, and the consequences are so devastating. The UV sterilizer is one gadget I recommend for those that "want to keep it simple".

Otherwise, you've got hobbyists with sick fish desperately dumping antibiotics, permanganate, copper and all kinds of chemicals into their tank. In my experience, treating sick fish is often difficult, expensive, and/or doesn't work. A UV sterilizer can help prevent much of this turmoil and unpleasantness.

For those that have healthy fish and haven't had problems, I salute you! You obviously have a good source of healthy fish and take good care of your fish. But you've also had a little luck. I've purchased many fish from hobbyists and stores that didn't cause any problems. But its that one asymptomatic disease-carrier that can spoil it all.

I just put my brand-new UV Submariner into the 50 gal. It's really nice and very quiet. Yes, it costs a little more, and I'll have to buy a new bulb in a year. But oh, the Peace of Mind! I've put all the fish that "look a little funny" into this tank [my fish that survived the mycobacteriosis outbreak in 2004 are probably still carrying the disease and could be infectious.]

Mister Green, I'm so sorry that your UV bulb was broken. I'm sure the vendor will take care of you. If they don't, you let us know!
See less See more
It depends on how coarse or fine the sponge is, most pre-filters are designed to prevent larger debris like plants leaves and possibly fish waste from entering the UV chamber. I don't think it would stop tiny shrimp, fry, rotifers or other small organisms from coming into contact with the UV light.
Dear Raul,

The sponge pre-filter on my Submariner is extremely coarse. I don't think it would stop anything but the biggest pieces of debris. The short exposure to UV may not kill small organisms like Rotifers and fish fry.

I will keep you all informed as to the filter's efficacy, etc. This is a "work-in-progress".

BTW, I will be giving a talk on mycobacteriosis at the Raleigh Aquarium Society's workshop in Feb 2008. I'll have more info then.
Hello Everyone,

Just reporting that I am very pleased with the Submariner UV sterilizer. It is quiet, and the UV light is still working (there's an indicator for light UV activity).

While I cannot predict what will happen in 2010 (or beyond), I can say that the Submariner seems to be working okay so far. I am sure that there are other UV sterilizer brands that will work fine. After all, it's only a matter of UV light hitting water-borne organisms in a way that maximizes UV exposure.

I believe that plants will remove toxins (ammonia, nitrite, H2S) and that UV sterilizers will counteract fish diseases (pathogenic bacteria, parasites, and viruses).

One needs both for a successful NPT.
No, but the club usually shoots for the last weekend in February.
That would be great if you could make it.
A UV sterilizer is a good to use whenever you add new fish. I keep one on hand for just this purpose. The one you bought sounds fine.

I don't think that you have to worry about snails and shrimp getting mycobacteriosis from whatever species of EM (environmental mycobacteria) that fish might be carrying. My snails did not get sick.

Humans getting Fish TB is fairly rare. Just don't clean tanks when you have an open wound, sores, pin pricks, etc. Unbroken skin is an excellent barrier to EM.

Parasites are probably a bigger problem with incoming wild fish than Fish TB. Read my article on fish diseases. Professional importers of valuable wild-caught fish often use a series of dewormers, including levamisole.

The UV will help, no matter what. It will help with bacterial infections secondary to the parasites. And if the parasites are small enough, it will kill them too.
See less See more
  • Like
Reactions: 1
These fish could be carrying parasites other than ich or just totally stressed out. That's sad that you're just down to one or two.

My aquarium club RAS does all their bulk fish orders only from the Wet Spot. Believe me, the RAS senior members are extraordinary picky, so I would vouch for the Wet Spot without ever having gotten a fish from them. I've never heard any complaints from RAS members-10-40 per year that get fish from these bulk orders. Cardinal Tetras, both wild and TR (?) are for sale for $3-4 each at Wet Spot.
  • Like
Reactions: 1
I envy you living in city with such a superb aquarium fish store.
  • Like
Reactions: 1
Please reread my article 'Mycobacteriosis in Aquarium Fish'. I used UV sterilizing filters successfully to manage an outbreak and prevent transmission to healthy fish. They did not cure sick fish. There is no realistic, practical cure for mycobacteriosis (MB) or "Fish TB." Routine antibiotics will not help except possibly for secondary infections that accompany the primary MB infection.
Good fish management (removal "of sick fish and UV sterilizers) will control and prevent outbreaks but will not cure diseased fish.
Article is available for free download from my website.
  • Like
Reactions: 1
1 - 13 of 60 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.