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Guest DaveOponic

Sick Koi - bleeding fins

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Guest 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

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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

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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.

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Guest 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

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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.

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Guest 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/fertilising/organic-based/dynamic-lifter-concentrated-seaweed-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

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Guest 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

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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?

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Guest 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.

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Guest DaveOponic

Did you do a 50% water change?

Thanks Jonathon. I changed half the water today and added some new filtration. The water looks cleaner tonight. I will have to look in the Aquarium shops tomorrow and see if they have sea salt and also a test kit that will keep an eye on water quality. I sure don't want to lose any more fish. Actually a bit of a worry losing a Tilapia as they are supposed to be disease resistant .... it was a smaller one ... presumably more sensitive to water conditions.

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Try to get an API Master test kit - it has everything you need to test for pH (both high range and low range), Ammonia, Nitrite and Nitrate. If you cant find one for sale im sure Murray could put a kit in the post for you.

Regarding salt - I use pool salt - seems to do the trick and its cheap b the sack. Just make sure it is 100% salt!

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Rapid pH swings can cause fish deaths alone and the smaller the fish the more sensitive. I would probably say that more fish deaths are due to pH swings than toxic levels of ammonia. pH swings causing stress on fish can cause Fin Rot to take hold on an injured fish. Your water change alone could repair any problems for a while but try to keep pH between 6.5-8 and adjust when it is close to the limits; Aquarium Salts will help too and perhaps you will never see a problem ever again. You said you have charcoal in your grow beds and being a new system I would have a tendency to say that your ammonia levels are pretty low anyway but even in a clear system it is hard to say what the pH would be, pH testing will help more than ammonia/nitrates tests. I don’t have a nitrate or ammonia test kit but I use my TDS meter and get a good guide what is going on there but regularly testing for pH. I also have a trickle filter with a conical floor I have recently set up using charcoal I couldn’t get a supply of charcoal so I made my own and it turned out perfect, additionally I have 15kg of shell grit to help as a pH buffer but time will only tell how effective it is.

Let us know how things are going.

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Guest DaveOponic

Thanks, I'll have a look for that test kit tomorrow. Actually I have been surprised by how problem free AP has been so far compared to doing HP. This forum is a source of inspiration. Much appreciated.:cool:

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what is ur TDS meter JD ? does it measures EC ? if so that aint too important unless ur running hydroponics and adding nutrients. the balance in aquaponics is more so related to ph amm. nitrites and nitrate. so how do u relate the EC value to this JD as I have an EC meter too but it never relates to my amm. nitrites and nitrate readings???? please explain ur way JD

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Dale,

An EC or TDS Meter can be used to check the nitrates of a system with an experienced eye. You said that it is used for hydroponics to measure nutrient concentrations, well the ammonia, nitrates and nitrates in an aquaculture set up is a nutrient concentration same rules apply, the more nutrients in a system the higher the reading of TDS. From that information with experience one can tell what is going on. What you said is correct to a certain point pH and ammonia relationship, but it is just another way of checking it and can be done safely, but it is a case by case basis.

You are running a salt water system, Completely different, the above rules really applies for freshwater only. Salt water has a reading of 35,000ppm of TDS (35ppt). There are many high concentrations of compounds adding to this reading where as only small amounts are adding to the reading of freshwater, ammonia then has more of an influence on readings, as such it is much easier to measure any changes in TDS of stable freshwater systems.

In saltwater systems evaporation rate alone could spike up the reading so yes, TDS is by no means is related to ammonia levels in such systems.

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Guest DaveOponic

I bought the test kits today. One kit for Ammonia and one for Nitrates. Both tests OK. No Ammonia at all and very low Nitrate reading. pH is fine too. I will keep a check on the pond until I have better filtration. I think my 100 litre grow bed is not enough to clean the water effectively and some solid wastes are getting through.

I was surprised by how many different test kits the Aquarium shop is selling.

My fish are safe for the time being anyway.

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Guest DaveOponic

My nitrate test this arvo. showed 5 mg/L. I changed the water yesterday, at least added about 25% to the pond. I think better too little than too much.

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Nitrate wont harm the fish and is needed for the plants. Nitrite is different and is poisonous to fish and so is Ammonia. Sorry if im telling you something you already know. Do you realise the difference between Nitrite and Nitrate?

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Guest DaveOponic

This is what I read about nitrates recently and it seems to confirm that my fish died because of the buildup of nitrates through overfeeding, poor filtration etc.

While I understand Ammonia and Nitrites are the fish killers it seems that both are the result of too much nitrate. Correct me if I am wrong though.

http://www.aqua-fish.net/show.php?h=aquariumammonianitratesnitrites

I found no ammonia and while I don't yet have the nitrite test kit, I suspect little nitrites. There was an acceptable ammount of nitrates (between 5 - 10 mg/L) So water change has worked and restored the balance.

But I can't agree from what I have read that high levels of nitrates should be in my pond. If I have enough healthy plants then surely the plants will keep the nitrate levels down?

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Hi Dave,

What you say is true but without testing ammonia (The more important one) and nitrates during your fish deaths one cannot be certain. Fin Rot is commonly caused by high ammonia/nitrate levels so it very may be true but not always the case. If your tank looked ‘dirty’ due to overfeeding etc high nitrates backed with the swing of pH it causes is a large candidate for fish deaths.

Remember the simple rule of Aquaculture: ‘The solution to pollution is dilution’ your water change has restored the balance and the additional filtration you have added should keep things in tacked.

But I can't agree from what I have read that high levels of nitrates should be in my pond. If I have enough healthy plants then surely the plants will keep the nitrate levels down?

It all depends. Climate, Nutrition, Plant, Variety, Season, Sunlight, Irrigation Timing, Plant Density, Water the list goes on. There is no set rule with Aquaponics regarding fish to plant ratio there maybe people reporting guidelines but are no true representation of what is reality in different circumstances. More plants will consume more nitrogen but you need to find the ‘balance’ between just enough for the plants while keeping nitrogen as low as possible in the water. If your water tests show low nitrogen then your plants should be consuming most of it (if not a deficit), its when there is high readings then you need to add more plants or control by a partial water change or both. But I would have the tendency to agree with you on that one as you have charcoal in your grow beds, that alone will consume excessive amounts of ammonia. Its no different people using ‘Carbon Filters’ (charcoal) to purify drinking tap water it removes chlorine and other pollutants, ammonia in the system is our pollutant that is effectively taken out by the charcoal.

How well is your water oxygenated?

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