Sick Koi - bleeding fins

[DaveOponic]

I had a dead Koi (fantail) last week. It was swimming in circles for a while and later just staying at the surface. Its fins appeared to be damaged and probably being picked at by bigger fish. I put it in an isolation pond but dead next morning.

Today I have another sick fantail Koi. When I took it from the pond I noticed some bleeding from the base of the pelvic fins. Its other fins were ragged and scales looked in poor shape.

These are the first two fish I have lost in about 6 months since setting up my AP system. Water quality looks OK. Clear and smells OK. Plants are all healthy and other fish look healthy.

Does anyone recognise this condition?

I don't have any measure of PPM or Ammonia only PH - I assume everything is normal but I'd hate to find more dead fish.


Dave

[GaryD]

Hi Dave,

From what you've described, it sounds a bit like Fin Rot.

Fin Rot eventually eats into the flesh at the base of the fin or tail. Was there any damaged flesh around the affected fins? Necrotic tissue looks washed out.....like a meat bait when it's been in the water for a long time.

The only dose of Fin Rot that I've experienced was cured with salt so boosting your salt levels to up to 6ppt might be a useful thing to consider. The fish won't mind it.....a bit of salt is a tonic for many fish.

Some plants won't like it so take account of that before you dose the system.

Gary

[Jonathan Dyer]

Hi Dave,

Definitely FIN ROT. You must act now or risk the loss of infected fish. I grow koi so I know, I have had a fish recently infected with fin rot but I haven’t lost it yet, the fin will heal and it is a real shame to spend all that time looking after beautiful fantail koi just to see their tails rot away.

Fin rot is a common disease and not contagious to healthy fish so don’t despair. Fin Rot is caused by a bacterium in your water, it is generally caused when the fish is stressed (pH imbalance and more so high ammonia) and/or physical injury fish nipping, sharp objects in your tank and this allows the bacterium to get a foothold on your fish and causes fish fins to rot, bleed, fray, swollen lumps; it starts at the tip of the fins and works its way to the body, generally by that time it is too late for the fish to grow back its fins and will die. Fortunately, it can be cured with antibiotics available at any good aquarium supply store.

Please try to follow these steps as closely as possible.

1. Do a 30% water change. Make sure your tank is clean too.

2. Go and get yourself an antibiotic to cure the infection. http://www.nippyfish.net/finlossfinrot.html is a good page on recommended medication.

3. At the same time get your self some Aquarium Salts and follow the directions on the label adding to your water aiming for the higher bracket rather than the lower dosages. Aquarium salts help fight disease outbreaks, reduces stressed fish, improves gill function and reduces healing time.

This should cure your problem but you must act now. As more than one fish has been infected I don’t recommend that you quarantine your sick fish it is not contagious and will reduce the bacterium in the water but there must be a quality issue or fish nipping going on to make it flare up, if the latter remove the aggressive fish if you can. Additionally, higher water temperatures of 24C + will reduce the bacterium growth but your water is more than likely that high anyway if not some heating wont go astray if only for a few weeks. A high protein or live/frozen food for a couple of weeks will help improve recovery time of your sick fish.

I hope this has helped. Let us know how it is going. But do that water change NOW.

[DaveOponic]

Thanks Jonathon

The fish is dead. I have been observing the others today and notice that they are kind of hyperactive, racing around the pond. I have several foot long Koi that appear to be bullying the smaller fish but only the fantails. The fantails I have are about half the size of these big guys. The Tilapia don't seem to be bullied at all. I haven't actually witnessed any nipping, more like they are playing chaseys around the pond.

I'm a bit loathe to use anything at this stage. All other indications are that the remaining fish are healthy and the water quality is OK.

One website I looked at today said that Fantails should not be in the same tank with Koi. While I don't want to lose more fish I think I'll hold off using any medications for another day or two. I have changed about half the water from my rainwater tank today.

Dave

Dave

[Jonathan Dyer]

Given a 50% water change and your other fish are not stressed it may be enough at this stage keeping a close eye. But I do recommend using some Aquarium Salts if possible. In my tank I don’t seem to have a problem I have near foot long koi mixed with various sizes down to 4cm. Keep your fish well fed and you may never have any trouble.

[DaveOponic]

One by one my small fish seem to be dying. This time a Tilapia. I noticed it yesterday hanging around at the top of the pond. It was not gasping for air and had no signs of fin damage or scale damage, no external signs of sickness. It was just listing to one side. The fish was still feeding last night but this morning dead on the bottom of the pond.

The only common pattern is that these small fish seem to be dying two or three days after I have sprayed my plants with seaweed tonic (Yates Dynamic Lifter - Concentrated seaweed plant tonic) I use the dilution rate from the bottle or less so I shouldn't be overdosing the system.

I have checked the MSDS for this product and it appears to be completely safe with no toxicity. (http://www.yates.co.nz/products/fert...d-plant-tonic/)

In my previous Hydroponic system I was getting good results with a similar product containing HUMIC and FULVIC acids. The improvement in root growth in particular was phenomenal.

I have noticed that after spraying the plants, the following day the water is brown for one or two days. I'm not sure whether it is coincidence or not but I have used it three times and three fish have died.

My water quality generally appears to be very good. I regularly top up my pond with rainwater and mostly the water is fairly clear without a strong fishy smell.

Has anyone used Yates seaweed plant tonic? I have seen a lot of references to Seasol so I thought I would try it but can't get Seasol here.


Dave

[DaveOponic]

How does the sea salt effect plants? I am reluctant to add anything directly to the pond that might upset the balance of the system. Generally, I have had no problems since I set up the system a few months ago. Always have good pH and although water quality fluctuates it is usually when I have sprinkled too much food in the pond or used a cheaper quality feed that clouds the water.

After the third fish death I am working on a biofilter this weekend. I will use a 200 litre PVC drum with plenty of aquarium foam of different grades.


Dave

[Hamish]

Do you test your water regularly for ammonia, nitrite and pH?

[Jonathan Dyer]

Hi Dave,

Did you do a 50% water change?

What is more valuable to you your fish or plants? As I said you run the risk of losing more fish if you don’t add Aquarium salts fast and you have already experienced the consequences, adding Aquarium Salts may have adverse affects on your plants but in the end does it matter losing a few plants at the expense of loosing many more fish.

Beyond doubt there maybe more health problems with your fish without toxicology reports on your dead fish and water one cannot be certain but poor health can have a chain effect spreading to many more fish; Fin Rot is not contagious from one fish to another but the bacterium in the water will attack other fish.

Adjust your pH to around 7 if you need to, this will reduce the stress of your fish if outside this level.

The seaweed extracts should have very little effect if at all to your fish; I use Manutec Seaweed extract I think it is slightly better than seasol but is more expensive as well but both give good results, I sometimes use Charlie Carp this has a soil wetter that can be toxic to aquatic life in some forms but I think it is pretty fish safe. There is another underlying factor responsible for you fish deaths other that Fin Rot. Perhaps pesticides/herbicides or contaminated fish food?

[DaveOponic]

Do you test your water regularly for ammonia, nitrite and pH?
Unfortunately I have no way of doing that. Here in Brunei there are no suppliers for Aquaponics/Hydroponics. The only test kit I have is the one I use on the pool that tests only pH and Cl levels. So I am flying blind without instruments.

I am working to get the best water quality I can. My system is totally DIY so it's all a learning process. I think I am only one of two people doing home grown AP here in Brunei.

So far I have only lost three small fish, so probably doing OK. The big Koi and Tilapia are looking strong and gulp down their food three times a day.

The aquarium shops here are fairly well stocked so might see if there's any test kits available for the ammonia etc.

Thanks again.