Backyard Aquaponics
A place to discuss aquaponics

I have a bunch of Silvers, some well over two years old that are covered in white dots. A few of the smaller ones have died already and I threw a few KG of salt into the tank a few days ago. Question is, should I go get more salt to put it in? I know I could put alot more in my 2500lt system. Will it cure them quickly enough? I was thinking of just taking all the fish out and eating them, then I could clean the entire system out while I'm at it!

CAN YOU EAT ITCHY FISH? If yes, thats what I'll do. I would hate for these beauties to die on me!

Cheers

Shaun

It might be nicer if you could cure them first and at the same time you could purge them in a high salt solution. If you search the forum you will find the rates or levels of salt which can be used to combat ich, but I reckon you could go with really high levels if you have another tank and that way it is separate from the plant side of things.

Just disolved and put 7.5kg of salt into the tank. How long will it take to cure? They haven't eaten in a few days already!

Cheers

Shaun

How long it takes to cure will depend on your water temps. Unfortunately the life cycle takes much longer in cold water and at current temps (I expect your water temps would be somewhere between 11 - 15C) you'll be waiting 2 - 3 weeks.

Unfortunately it appears I won't have 2-3weeks as I don't think they will servive that long! I pulled out another 4 dead ones this morning. The smaller ones are dying first but the big ones (1kg+) are sluggish and look as though they are covered in small bubbles. It's actually slimey dots but thats what it looks like.

Can you eat them or has 2 and a bit years of work and food just been a big waste of time?

Thanks for the input, I appreciate it!

Shaun

I always work on the basis that you have to be able to enjoy them, and from what you've told us it would not be enjoyable, whether they are actually safe to eat or not.

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If you can warm your water up to 20C plus you can cure them in less than a week. If thats not possible I cant see why you couldnt fillet them and eat them.

The parasite lodges under the scales... so if you skin the fillets... they should be fine...

Surely even parasites are ok if cooked properly

With your water temp it is going to take probably around 3 weeks

Heat treatment is best, 30 degrees or more kills it pretty quick.

Another trick is to give them a straight tap water bath for a couple of minutes. The chlorine will kill the parasite.
Dont tell aquarium owners that trick though, they will have a heart attack

Thanks all.

Lost another 10 fish yesterday so they all come out today!

At least it will give me a chance to clean the gunk out the grow bed and tanks ect.

Cheers

Shaun

That sucks MM

I posted this in another thread but I think it is very suitable in this discussion. Shaun, with your 2500 litre system you would have needed 25-30 KILOGRAMS of salt (I used ordinary swimming pool salt). You could have used a smaller tank and heated that water with a 300W heater. The salinity needed to be > 10ppt (mine ended up at 13.5ppt). Heat and salt will kill this parasite. Mal ........


This may be a bit late for you, but will be of benefit to others.

Last year I lost 11 barra @ 1.5 kg to Cyclone YASI. (no power for 36 hours)

I replaced them this year with 20 x 7" barra and broght them up to ~ 1.6kg. 'chainsaw' and I ate a couple for our 70th. Not long after 'chainsaw' returned south my barra started keeling over (homesick for 'chainsaw' ). AT 18c he kept telling me my temps were too low (in the tropics admit at lower level). Barra weren't eating for two weeks. I went to local aquarium shop and bought 300W 1000 litre heater for $85 .... even if I could get the 3500 litres over 20c it would be better.

Arrived home and went to insert heater. Three on the bottom and a couple coming to me on top to help them. Now I'm no mind reader, especially with fish, but I just knew they wanted to be out of that water. Everything else, Oxygen, Ammonia, Nitrates and Nitrites were all in specs.

8 O'clock that night I made the decision to get the final 10 out of the tank and into the 1000 litre aquarium with my two 'pet' barra. (some of you will remember that I mass-murdered the other 48 of them with overdoes of salt). During the night I kept checking and removing one or two dead barra. By three o'clock the next afternoon I hade one left floating on the surface. Picked him up, with help of a cloth, and knocked him on the head. Not wanting to lose my two pets I rang Qld DPI and managed to get through to Principal Pathologist (fish diseases). Prior to going to the lab I drained my aquarium to 50% and threw in a couple of GOOD handfuls of pool salt and PLENTY of oxygen

Within 1/2 hour I was at DPI and we had the last fish on the morgue bench. Cut off pieces of the gill and under the microscope where he identified 'Ich' (aka White Spot). There was NO WAY I could see anything wrong with the barra by just looking at them with naked eye.

The Pathologist was confused as to how the 'Ich' was introduced to my system. I finally remembered that I'd bought a few 'golfish' from local aquarium shop for the fish pond. I managed to kill them TOO!! Within an hour they were dead. Forgot that a couple of months previously I had a Chlorine tablet in that pond to reduce algae. I fed ONE dead guppy in the aquarium and one guppy to the 17 barra. Ah! he said, that was the carrier.

Now knowing the cause, my goal was to save the two pet barra in the aquarium. My advice was to take the water to 10ppt salt and 30c. I'm lucky enough to live alongside a poolshop so every half hour or so I'd take a sample of water down to measure the salt. First time it was 2628ppm. She said "Your salts down a bit". After explaing that it was for my fish tank NOT a swimming pool we managed to conclude that my aquarium was ONLY ~2.6ppt. After about four trips I managed to get the tank to 11.5ppt and 30c (had to add a second thermometer to get that high).

I'm pleased to report that barra are now back eating (smackingly) and look really healthy (that real silver sheen that you only see on barra in salt water). Water has seen 50% change and salt level retained ~11.0 ppt. Tank is wrapped in polystyrene panels during night (ambient gets down to 14c) and removed during day.

Next week I'll do another 50% change and start reducing salt to 2ppt. (I want to put a blue gravel filtration bed in behind the tank so water exits top of aquarium into growbed full of blue metal and back into normal aquarium filtration system).

My two pets are around 400-450mm and 1.5kg. They will NEVER be bound for the table.

You know: NEVER NAME YOUR ANIMALS! These two are Malcolm and Rodney

HTH

If you pull sick fish from a large system and put them into the saline, warm, well oxygenated hospital system which cures the fish, how do you cure the large system into which the fish will have to eventually return?

In my aquarium days (many years ago now), ich was treated by removing the fish to a hospital tank, draining the aquarium for four days or longer (best if left in the sun and/or regularly heated with Mum's hairdryer) and must remain completely dry and warm (27C+) for the duration. After four days, flush the system and all components/accessories with formalin (formaldehyde) (and/or strong solutions of potassium permanganate and/or chlorine bleach) rinse well with fresh water and dry again, leave overnight then fill then next day. Whilst all that was going on, the fish in the hospital tank were treated with heat (24C+ for goldfish, 27C+ for tropical) and weaker formalin solution for the duration, with twice daily water changes and chemical refreshing. The parasite is almost impossible to kill without killing the fish but has a short lifespan, so the aim is to kill the theronts before they find their host as the theronts only survive for a few days without a host. Although formalin is pretty cheap to buy in bulk, it's still going to be expensive and very hard to do the same cleaning routine on an AP system as you'd have to de-construct the GBs in order to dry the media; not to mention that formalin is exceptionally toxic to any living animal including humans and if it doesn't kill you outright, then you'll probably end up with cancers or at the best case it's a potent irritant. The formalin has to be very carefully mixed when used to cure the fish as if you get it wrong you kill the fish anyway! Nasty stuff, but it works... in the small aquarium context.

MalcolmC, perhaps you could put this to your pathologist: Is it possible to cure a large AP system of ich in the same timeframe as the fish in the hospital tank? Obviously it's going to be "expensive" to heat and salt the large system; is there an alternative method to kill the parasites in a large system than salt and heat, or toxic chemicals?


Scott

Hi Scott

I had already asked the doc that Q. Because we are in a "closed" system the parasite no longer has a carrier and will eventually die out in a few weeks. I know I do have worms in the GB. IIRC he said would not affect them. At present I have just turned it into a hydro system with doses of "Seasol" to keep the tomatoes and Silver Beet going. I'll throw in a couple of canaries and wait another month when I'm ready to start again.

I never had ANY distinctive marks (i.e. White Spot) on the Barra; at least not until they were dead and the doc pointed to one that was just forming on the "dorsal fin" (technical name for CRAFT fin)

Mal