FISH PROBLEM - Hybrid Striped Bass

[nwestwood]

I added 130 fingerlings to my 300 gallon system last Thursday. A few were belly up the next day, and I chalked it up to travel loss. Then a few more the next day and the next. Sunday, I tested the water and Ammonia was 1.0, Nitrites were .5 and Nitrates 30ppm,PH of 7.0 temp 74 (23C).

The Ammonia may have spiked higher in prior days and I didn't catch it. I did a partial water change and the next day, the levels were back to normal, but there were more fish deaths (7). Then Monday 5 dead, Tuesday 4 dead and this morning 8 more.

The nitrate levels are going up, It looks like they are over 50-60ppm now (normally they run 10ppm). I did another partial water change this morning.

The fish begin by starting to swim slower, tipping side to side and upside down. If you catch them they still respond and try and get away. They appear to have a mucous or fuzz in front of the eyes (maybe from the eye socket). If I catch these, the fuzz comes off (like wiping a runny nose kid). When they die, it's with their mouths wide open and they sink to the bottom. At no point are they gulping on the surface, so I don't think its oxygen.

The dead ones look like they have blood vessels in the head and front that are burst (discolored through the skin, not seen in healthy fish).

The DO levels are 7.0+ in the day and early morning test show its 5.5+ early.

Is this still a result of ammonia levels spiking? and I'm just seeing the tail end, or is this something else.

The Bluegill and goldfish in the system are un-affected. The fish came from a tested regulated farm (tested the week of the shipment - no diseases).

Anyone ideas? Help.

[bunya boy]

Stop feeding.
With Nitrates that high, the fish are producing too much bio-load for your available GB space.
Get more Grow beds, plant more plants and don't feed for a few days. Do water changes but beware of quick fluctuations in temperature, pH and D.O., these will also be the demise of already stressed fish.

IanK

[nwestwood]

I stopped. More data. 4 more gone tonight. I did another 20-25% water change. There is a lot crude in that tank that is not ussually there(the water is clear, but this stuff settles to the bottom.), also floating is what I would call feces except it hangs together like a small worm would, but I'm sure it's not a worm. It might be pieces of intestine, it has a light casing on it.

Also, I have a larger particle fish food that I'm grinding to fines to feed. I ussually grind a couple of weeks worth and stick it in a zip lock bag in the greenhouse. Could this be spoiling in the heat? Should I be storing it in the refrigerator or freezer and pulling out just what I'm going to feed?

I have located another tank to cut a bed out of, and already have a space for it, and the plumbing is already in. I will get it added to the system, even so, I would not have thought a bunch of little fingerlings could cause such havoc. They are tiny fingerlings.

Anymore advice and guesses I welcome.

[bunya boy]

:( Hi NW,
Yes, they may be tiny but they still produce a load of nutrients. 130 to a 300gal tank (that already contained fish?) is a hell of a load IMHO.
I am only going to put 50 maximum into my 900 litre tank (about 300 gal) and I have 4x130 litre GBs, which will be cycling from a couple of months of continuous "Seasol" operation without fish. This is to allow sufficient bacteria to colonise the system before adding Fish. Plants will be producing in the mean time.
I think you have just gone too big with fish too quickly. If you are getting high Nitrate readings, it would indicate to me that your system is cycling correctly ( i.e. your Ammonia is being converted to Nitrites and Nitrites to Nitrates) it is just that you don't have sufficient Plant life to take care of the ammounts being produced. Nitrates in high levels can be just as destructive to Fish as high Ammonia and Nitrite levels.
I don't know what the solids are that are floating, but the floculating sediment could be anaerobic fish food that has rotted and clumped. This crud can drastically lower your DO levels, especially if combined with elevated temperatures.
If your floating stuff looks like intestine, then it probably is! Rot gut can be caused by anaerobic conditions, fetid food and high temps,; combining to produce almost septic growing conditions which will surely kill your fish.
The smaller the fish, the larger the consequence. Certainly refrigerate your food for storage, it will help keep it fresh. Other than that, up your GB area or keep less Fish.

Hope you get it sorted soon. I hate to hear of fish deaths.

Cheers IanK :D

[GaryD]

Hi,

I don't have the time to read through many posts right at the moment, so excuse me if I ask questions about your systems that I otherwise ought to know.

Are these fish in the same water column as your other fish (albeit in a different tank)?

What is the average daily ambient temperature - minimum/maximum?

How much water is in the tank that contains the dying fish?

Gary

[Ravnis]

I would suspect this from your description.

http://freshaquarium.about.com/cs/disease/p/columnaris.htm

Notice that a treatment listed is salt which is the prescription of choice.

Salt causes certain types of bacteria cells to swell. THe fish cells can handle it; the bacteria's can't.

Melafix does wonders... but with it stating not for use for food fish, I would hesitate to recommend it. It is my opinion they just didn't want to hassle with food and drug testing. This is my opinion though and not based on any known fact.

[nwestwood]

Gary, Yes the fish are in the same tank with the Bluegill, daytime water temps were 74 (23c), night time 70(21c). the tank volume is 275-300 gallons (1000 litres) with about that much more in grow beds and DWC and sump tank.

Ravnis, I looked at the description for columnaris, it might be this, but it's not white spots or saddle back, in some it looks much more like they had a chunk of fuzzy mold 1-2mm on the front of their head.

I've done more research on Hybrid Striped Bass (HSB). Rebecca Nelson from Nelson and Pade in the book "Aquaponic Food Production" states: "The hybrid striped bass, ..., is not a good choice for aquaponics because they are reported to have a low tolerance for potassium, an element that is sometimes supplemented in aquaponics." Although HSB is a good choice for recurculating aquaculture where you don't supplement other minerals, it may not work in Aquaponics.

I do supplement potassium. I've done more searching and found several research articles on the subject and have emailed the authors for more information. HSB were not my first choice, but the only other warm water choice approved by the State. Maybe I'll have to stick with Bluegill until I can apply for an exception to the rules.

I lost more overnight, It hasn't changed yet. But still no problems with the older Bluegill and goldfish in the system. I stopped feeding completely yesterday. The water is clear (except redish from iron). I've been adding ice to keep the temperature down below 74 (23C). And doing partial water changes daily. The nitrates have dropped to the normal 10-20ppm. Dissolved Oxygen remains above 5.5 usually it tests 6-7.

I've frozen a few of the recent deaths and may send it to a lab to find out exactly what it is. But, HSB may not be a good choice for aquaponics.

[GaryD]

Hi,

Let's look at some of the factors involved in your situation:

You're keeping HSB and they're not recommended for AP.
HSB and potassium-sensitive and you're using potassium.
You have several different breeds of fish in the same tank - this works in very rare situations - is likely to be causing stress to the smallest fish.
You've got a disease of some type - further evidence of stress.
You appear to have had quite high ammonia and nitrate levels - affected fish may have bright red gills.
The fish are dying with their mouths wide open - suggests oxygen levels might be a problem. Your temperatures would aggravate any tendency toward low oxygen levels.Any one (or a combination) of the above might be the explanation for your problem.

I'm a little surprised at the fact that you have elevated ammonia levels given the number of (what I presume to be) fingerlings in your tank (1100 plus litres). Do you have uneaten foot in your tank?

The nitrate levels (30ppm) are not an issue. Nitrate is nowhere near as toxic as ammonia or nitrite. Nitrate levels may be as high as 400ppm in some systems.

I'd boost oxygen levels immediately.....dose with salt......and stop feeding until your ammonia and nitrite levels recede.

Gary

[nwestwood]

Gary, There was a bunch of crud in the bottom of the tank a few days ago. It's cleared now. I didn't think I was over feeding, but if the bluegill stopped eating due to the introduction, then it's possible. It's clear now.

I have cucumbers, tomatoes and lettuce growing, will salt hurt any of these?

What type of salt is best? Will water softener salt be sufficient or do I need to buy aquarium salt to be safe?

[GaryD]

Hi


Gary, There was a bunch of crud in the bottom of the tank a few days ago.
Crud (whether it be uneaten food or fish wastes) will eventually become ammonia and will consume oxygen in the process. If your system was low on oxygen (and at your ambient temperatures it may have been borderline) the muck on the bottom would not have helped.


I have cucumbers, tomatoes and lettuce growing, will salt hurt any of these?

I'd be thinking of 1 or 2 parts per thousand - shouldn't be an issue for the plants.....and it will act as a tonic for the fish.

Use salt that has no additives.

Gary

[nwestwood]

I setup a seperate 150 litre or so tote added tank water, salt to 3 ppt and stuck an air stone in it, then netted as many of the fingerlings as I could (fiesty buggers for being sick).

Now I have 90% of them in a controlled environment (albiet stressed yet again from the netting).

Back in the full system, I added 1 ppt salt to support the few fingerlings and the bluegill that are their and not knowing what 3 ppt would do to the plants, I was nervous to treat the main system as heavy as the treatment tank.

Now the question is, how long do I leave these in the treatment tank? Should I up the salt dose in the smaller tank?

I'll have to change the water periodically as it's not an established tank, but if I don't feed them, they should make it a few days before ammonia starts to climb.

Any thoughts on how long they should stay there?

I'm considering a 4 day antibiotic treatment as well, just to clear them up well.

[GaryD]

Hi,


I setup a seperate 150 litre or so tote added tank water, salt to 3 ppt and stuck an air stone in it, then netted as many of the fingerlings as I could (fiesty buggers for being sick).

Now I have 90% of them in a controlled environment (albiet stressed yet again from the netting).

Back in the full system, I added 1 ppt salt to support the few fingerlings and the bluegill that are their and not knowing what 3 ppt would do to the plants, I was nervous to treat the main system as heavy as the treatment tank.

Now the question is, how long do I leave these in the treatment tank? Should I up the salt dose in the smaller tank?

I have no experience of HSB so I'm probably not the best person to offer advice. In general, it's unlikely that 3ppt will do any harm. As for whether it should be higher, I'd be talking to the hatchery that supplied them or someone else with experience of them.


I'll have to change the water periodically as it's not an established tank, but if I don't feed them, they should make it a few days before ammonia starts to climb.
Bear in mind that they produce ammonia throught their gills so, as long as they've got anything inside of them, you're likely to get ammonia.....so test every day.

Gary

[Ravnis]

http://www.ncseagrant.org/home/resource-library/free-information-and-guides?view=showProducts&id=32

While this may not be fast enough to help you with your current situation, you might find some useful information here.

Prime is useful in not only removing chlorine, but it also make ammonia and nitrite convert to less toxic forms.

There are harmful bacteria that convert ammonia to it's other forms that grow first when new fish are added or water temperatures suddenly make a major rise(ie 15-20 degrees), until the beneficial bacteria starve them out. This is a common problem with people that keep koi in unheated ponds. It may be that this problem with fix itself after a few days to a couple of weeks provided you have enough biofilter to fish ratio.

If you use sea salt like that sold for salt water tanks, your plants will actually use it as nutrients as well.

[nwestwood]

Ravnis - After seeing this in more advanced stages, I now think you were right this is Flexibacter Columnaris (aka cotton-mouth, saddle back). It was a vicious case, going from spots to massive fungus overnight. Since I added the salt 8 hours ago, just 1 death, and it was one that I should have pulled out as it had no chance. I can see a couple that had massive saddleback growths, the growth is gone, but the scar remains, they are swimming well so we will see.

In the main tank, the few fingerlings that remain look healthy, I don't see any with big lesions or spots, especially now that the salt in the main tank is at 1 ppt.

I also treated with a triple sulfa in the medication tank. It's a four day treatment, adding meds every 24 hours. I'm going to test ammonia morning and night, changing water as needed and give them 4 full days in the medication tank, then I think I will transfer them back to the main tank. I'm also watching the plants closely in the main tank to see if they react. If they show problems, then I'll do water changes there to lower the salt level, but from the comments here, what I've read and seen, I think they will be ok. I do have 2 strawberry plants in the DWC, and they may not like it, but I can do without them if the fish get better.

Next time I believe I will start with the fingerlings in a treatment tank, give them a good salt treatment for a week or so and then move them to the main tank. I'll report tomorrow on the progress of the 2 tanks. Thanks for everyone's input.

[nwestwood]

Just a quick update. Today I'll add the last dose of Triple Sulfa to the treatment tank and tomorrow they will go back in the main tank.

The first 24 hours of treatment I still lost 7 fingerling's. The second 24 hours only 2, but 2 again this morning. I'm doing a 25% water change morning and night in the med tank (re-adding salt and meds) to keep the ammonia levels down. In the main tank where 10-15 remained that I couldn't catch. I've kept the salt at 1 ppt or so. I had 1 loss the first night and none since. I suspect it was the strong ones that I didn't catch and the salt has helped them.

The cotton-mouth and saddle-back lesions and growths are all gone, I don't see any disease on any of the fingerling's in either tank now.

I've received several research papers on HSB and Potassium. My problems are not that. HSB are about as sensitive as trout, and if you exceed the lethal level, you will have 90% of the deaths occur within 12 hours, not a few a day.

I'll keep running salt at 1 ppt in the main system for a couple of weeks. The plants show no problems at all and continue to grow, flower, and fruit. Even the strawberries have shown no effects so far.

I'll post an update in a week or so on how the fish and plants are doing.

[GaryD]

Hi Neal,

As someone who grows murray cod, I can empathise with you about fish losses that confound.

While you obviously had a problem (given the lesions and the cotton-mouth), we lost fish over a period of months and we simply couldn't arrive at any explanation. Even we spoke to people who hade extensive experience of murray cod, all we could get out of them was "that's murray cod for you."

I hope your journey get easier from here on in.

Gary

[nwestwood]

The HSB fingerlings are back in the main tank. There have been 2 more fingerlings die, but none in the last 24 hours. Unfortunately, over the last 3 days I have lost 2 bluegill. I can't tell why these died, they are good sized and I can't see any signs of disease, but assume that they are catching the same thing.

I called a national fish food supplier who can provide medicated feed, but only in 50lb bags. They suggested I call a hatchery, they had heard of hatcheries mixing feed with vegetable oil and then mixing antibiotics with it.

I called the supplier of the fingerlings. They have never treated with antibiotics, but did say they know of hatcheries that do mix vegetable oil and antibiotics. He did not know dosage, but felt that you couldn't kill fish by to much antibiotics. He treats by putting fish in a tank of 20 ppt salt for 24 hours, then out. If needed, he repeats it, but realized I couldn't dose the plants that heavy.

So, I went down to the farm supply store, bought 6oz (186g) of generic terramycin (oxytetracycline hci). Then put a cup of fingerling food on a plate covered with wax paper. I added 1-2 tablespoons of vegetable oil. mixed it with a fork until all pellets were coated. Then I sprinkled the antibiotic powder on top, then mixed it well until it was totally absorbed by the oil and pellets.

In my tank, I turned off the air stone and took off the water sprayer so I could see well in the tank (no surface disturbances). Then I fed a spoonful at a time, waiting until the fish had eaten all I put in, repeating until the fish show signs of not eating. I'll feed 2-3 times a day for 10 days with the medicated feed. (don't forget to turn the air back on).

After that, whatever happens, happens and I'll let it run it's course. I thought others might find this technique useful.

[GaryD]

Hi,



I thought others might find this technique useful.

Experience......good or bad.....is invariably useful.

Gary

[nwestwood]

Just a quick update. The Hybrid Striped Bass are doing well and growing nicely, no more problems. They now share the tank with Rainbow Trout as well. Potassium does not seem to be a problem. My tank tests at levels of 30 - 50ppm and no deaths. I think the rumor of HSB and potassium problems come from studies of the use of Potassium Permagenate, a common practice in pond systems, and it is Highly Toxic to most fish, especiall HSB and Trout. But it is the Permagenate that is toxic, NOT the Potassium. While both HSB and Trout are considered harder fish to raise, I would much rather raise them than the Blue Gill, both grow much faster, feed frenically and are doing well.

[kellenw]

How big are the BG compared to the HSB? Remember, dead fish also cause ammonia spikes, compounding the problem.

One thing is for certain, you are going to have WAY too much biomass for that system as these guys grow. In fact, you already have too much right now. Now, imagine what it would be like with 100 1 pound HSB and a bunch of BG and Goldfish too. It is very important to understand the carrying capacity of your system.

As a bandaid fix, I recommend adding some mechanical filtration right away. You probably should vacuum or syphon solids from the tank daily for now and replace about 10% of your water every other day as well. When you see N and Ammonia begin to decrease, begin aerating like crazy (but not before you see ammonia and N begin to decrease or you'll make things worse).

Also a pressurized sand filter would help with ammonia and N issues. Without going into the technical aspects, the sand filter (which is really just a biofilter using tiny grains of sand for bacteria surface area) will help breakdown the nasty stuff into more easily absorbed nutrients for plants (and less harmful for fish). Put the sand filter in line with your hose that feeds your growbed(s) if you can. However, in your case, it MUST be cycled outside of your tank for the first 14-21 days, or it will initially make your problem WORSE.

Then, down the road, add a ton more growbed volume and a huge sump to add more water volume to deal with the biomass. More water = less problems.

[nwestwood]

I've updated my regular forum but not here. The tank now has 98 Blue Gill (3" to 7"). 64 HSB all about 5-8" and 55 rainbow trout 5-8". The medicated feed back in July stopped all the problems and there have been no deaths since. Nitrates do creep up and ammonia is consistently around .5ppm. At on point about a month ago, all levels were climbing, but I found increasing the flow rate of the water cleared that right up. I have a 3rd grow bed to add to the system (when I get a break, it was minus 5 Fahrenheit last night). I test all levels regularly and will make changes if anything gets out of control. All the fish are growing well, I think next month we will start eating fish fillets for dinner.

[kellenw]

Really glad to hear you got things back under control. Well done!