Backyard Aquaponics
A place to discuss aquaponics

Hey EB, not mine.

Scott, the systems are separate. The barrels has 9 goodies and 10 SP with 150L frowned. All is well there but can't put more in or mix them. It is 5-6 months old

Nitrite poisoning is also known as 'brown blood disease' because the blood turns brown from a increase of methemoglobin.

Methemoglobin causes a more serious problem than changing the color of the blood. It renders the blood unable to carry oxygen, and the fish can literally suffocate even though there is ample oxygen present in the water.
Different species of fish tolerate differing levels of nitrite. Some fish may simply be listless, while others may die suddenly with no obvious signs of illness.

Common symptoms include gasping at the surface of the water, hanging near water outlets, rapid gill movement, and a change in gill color from tan to dark brown.
Fish that are exposed to even low levels of nitrite for long periods of time suffer damage to their immune system and are prone to secondary diseases, such as ich, fin rot, and bacterial infections.

As methemoglobin levels increase damage occurs to the liver, gills and blood cells. If untreated, affected fish eventually die from lack of oxygen, and/or secondary diseases.

I would inspect the gills and even perform an autopsy to inspect blood and internal organ colours and condition.

And of course do a nirtate test to see if you at least have some form of nitrate colony developing, I would also seed the new system with more water and media from your old system during water changes with added salt to 3-4ppt.

Good luck mate and keep us posted, hopefully we can help get you though this.

+1

Take half the water from the old system and replace it with clean water (normal precautions). Salt the extracted old system water with up to 3ppt (up to 3 kilograms of pure (pool) salt per 1000L of water) and add this to the new system. Repeat daily until conditions improve. Can you redirect some of the new system water to flow through the old growbed and still have it return to the new system FT? (There is a chance of spreading a disease, but if we presume the fish deaths thus far have been caused by the nitrites then it might help the system establish sooner.)

I had another death today. See pictures below, unlike others this one had gills flared.




I did a 30% water change yesterday afternoon (re-salted) and I realised on the other days when there were no deaths I hadn't done any water changes due to me being sick. Then the statement "normal precautions" stuck out in my head....I am in Perth metro and was of the understanding that we didn't need to do anything to tap water, is this another lesson

For my small system I have never aired off the water, just filled up sump level straight from hose.

Should I be airing off the water before changes?
Could the death just be nitrite related, or does the water change have impact?
Could the water change have impact because nitrite poisoning has weaken fish?

I am still to do the water change from the small system.

I got a nitrate test kit and the reading is looking about 20-40ppm, I guess it is chugging on the nitrites:

Have you had any rain recently. I was wondering about zinc runoff from the shed.

John Fenn

"Normal precautions" includes such things as making sure the pH and temperature of the fill water is the same (or close to) the water already in the FT to avoid shocking already stressed fish. Perth's water is supposed to be OK in terms of chloramines and other additives, so the biggest problem with tap water is that it is not well oxygenated (which is why if you leave the hose running into the FT all day, all the fish die!) Some areas (in the NOR from what I have been told) have high levels of chlorine, so it's worthwhile allowing the water to stand for 24 hours or so to off-gas, or this time can be reduced by adding an air-stone.

Make sure you buy a tap timer... cheap insurance from an HSM!

It's a bit hard to see the true colour of the gills in the picture because of the pink netting, but the gills look a little dark, brown? The gills should be bright in colour, deep pink to red, they should look "good" and "healthy" (sort of hard to explain, but next time you harvest a healthy fish for dinner check out the colour of the gills) whereas in the photo it looks sort of "mushy", "sickly"?

This is excellent news, it means that if you haven't been adding anything from anywhere else, the nitrates are the result of the nitrites being consumed and converted. Time and patience now, keep up with the water change, salt as required and avoid feeding.

Hi John,

The shed should be colorbond, with light rain it won't run into growbed but heavy like a couple of weeks ago it may run in. This weekend I will try and put some form of gutter on it and catch it in a drum.

For now I just cycled 100L from the Barrel system into the IBC system. Barrel system looks ok; Am=0 Ni<0.3 Ph=7.5

With regards to no feeding, It has been at least a week. I know a few days is ok, but how far can I push this?

It's been at least a week, then give the fish a SMALL feed. That will keep them going for a day or two, then MAYBE another SMALL feed then.

Itys hard to tell, but the gills do look a bit darker than they should. Im still thinking nitrite poisoning.....but I may be wrong.

Don't want get hopes up but I took a reading this evening and nitrites are coming down, look to be
0.8ppm...now other measurements have been at midday so does that make a difference?

Been topping up from small system in 100L per 2nd day. No deaths.

Thanks guys.

Unfortunately, the nitrite effects will affect the fish for its entire life.

What will be the affects; stunted growth, susceptibility to disease?

Well a good experience to learn from.

Forget where I got this snippet -- but like all things there are some scientific papers which agree and some which don't:

"Fish that are exposed to even low levels of nitrite for long periods of time suffer damage to their immune system and are prone to secondary diseases, such as ich, fin rot, and bacterial infections. As methemoglobin levels increase damage occurs to the liver, gills and blood cells. If untreated, affected fish eventually die from lack of oxygen, and/or secondary diseases."

I have a paper somewhere which basically says only certain types of fish suffer long term effects, and another paper which "debunks" long term effects for all fish species.

Prepare for the worst, hope for the best.


Scott

Note to self: must try to fix that dead hard drive that we thought didn't have much important information on it!

Well nitrites have come down.
They are 0.3ppm

Thanks Scott & Charlie.

So my plans now are to ..... I will see. I am not sure if I should just leave the system with the 4 remaining trout or get a couple more, say 5. I think what I will do though is organise more growbeds and then figure out about stocking.

I need to find 2 more IBC for now.

Thanks again.

I'd leave the system with the 4 survivors in there. Get your new IBCs and make up and plumb the new GBs and plant out. Cycle the new GBs for 3-4 weeks to colonise them with bacteria, then add fish.