Backyard Aquaponics
A place to discuss aquaponics

Yeah that might be a good course but what backyarder has an accurate idea of how many kgs of fish they have in their tanks?

sorry i should have explained that better, i meant per 10kg of food. As its mixed into the food. then just feed them 1% body weight.

its meant to be mixed up everyday fresh aswell.. but in this instance i would just make up however much you would normally feed in 10 days and then store in fridge.

So they would still need to know their weight in fish in their tank then.

Yeah but that means that they could be way over dosing or under dosing.

Without getting a reasonable idea of the biomass how would they know? I'm not a vet so I don't know much about this but I do know a fair bit about medicines in humans. Dose is seriously important not enough and it is worse than a complete waste of time too much and the consequences depend on the medication.

I say worse than a complete waste of time because IF the problem is bacterial under dosing just makes for stronger infections.

ive seen vets prescribe double doses, ive also seen some very large guestimates on both fish numbers(to the closest 5k) and fish weights. It all works, i believe oxytet is a bacteriostatic AB in that it doesnt kill it it merely interupts their reproduction and lets the fish's own immune response do the cleanup. The only risk with underdosing is that its ineffective and may lead to potential AB resistant strains of the disease, very small risk. I would err on the side of underdose and just make sure all environmental factors are correct so the fish's immune response can take back control, it wont need much of a helping hand.

in optimal conditions trout will eat 3% body weight, but in aquaponics with 1 feed a day it would be pretty close to 1%.

Hello again!
The situation is becoming worse, but now I have a strong suspect that the problem may have come from a poultry house that is operating by seven weeks. As it is known , poultry litter spreads in air ammonium ( it can cause acid rain) which may have affected water parameters and the nitrogen cycle has changed.
The picture i am posting shows a map ( 20 m scale ):
Black square is the poultry house.
Red square are my father's tanks.
Orange square is where our fish food stays.
Blue square are someone else's tanks.
The other light blue square is where the other's person fish food stays.
The blue arrows shows the direction of water flow.

The other's person fish has no serious problems ( 4-5 dead fish per day).
Do you think that the poultry is causing this?

Thanks!

I'm still curious about your water temps, google says its getting to 34C in the next few days, depending on water volume, that's past the point they usually survive there. Too hot.

I'm sure you know this Column but its the water temp that is important not so much the air temp. Last summer we had several days in a row over 40c. My fish where fine because we tend to have cool nights during hot weather (clear skies) and I've got a relatively large system.

Plus I don't think that the pop eye sympton is a temperature related problem. Unless of course they are suffering from gas bubble disease and the warmer temps are releasing more N from the water into the organs of the fish.

Is there any compressed air being used in the system?

The wind borne ammonia could be an issue but I don't have any experience with this. Disposing of the waste is another matter but our wind borne concerns were more dust related.

I know that, but I'd like to rule it out. Many people expect they are going to die when summer hits, so they grow them out, and when one or two start to die, they knock them on the head. And we don't have many details about agim's system, so I don't know the size or anything. Easy enough thing to check though.

And I agree with the others about the eye getting pecked out by a bird, it didn't look like the freshest fish.

Fair enough.


Yes despite having asked. Twice.


There was a photo of a fish alive with its eye popped. The first photo looked like it had been left in sandwich press with the power left off.

poultry are certainly not the cleanest of animals.. but you say the water flows away from your farm towards the chickens.. so i dont know.

The water temperature today was 24C, but this is not the hottest summer of all these years, and we have had no such problems before. The disease has begin from the tank near the poultry and has expanded in the other tans in the reverse direction of the water flow. It also has begun nearly in the same time the chickens have arrived in the poultry and it has begun working.

well that would imply very poor biosecurity if your spreading disease against the flow of water. 24 degrees the fish's immune system would be just about shot and is prime bacteria breeding temperature.

With the limited information we have i can think of nothing better than to go ahead with oxytet, i believe its initial use was in poultry and has been adapted for fish and it is a broad spectrum anti-biotic, if its a disease from chickens it will fix it.

Your operation looks more like a commercial fish farm than a backyard aquaponics operation, surely you have a health authority you can consult and send samples to for testing?