Backyard Aquaponics
A place to discuss aquaponics

I have been hit by the dead fish syndrome and need some help.

Just had 26 out 50 floaters/sinkers. All have died with mouth wide open, so I have a feeling that it could be low DO levels.
My system usually cycles every 2 hours, however it looks like there may have been an overflow in one of the growbeds and thus the water level in main tank has gone too low and therefore the pump has not worked due to the safety cut off from the float switch.

This is what I think/hope but want someone else to look at these photos and give me their thoughts.

Ammonia was at 0.25
Nitrate at5= 5
Nitrite at 0.25

Haven't checked PH.

Of the remaining fish all were gulping for air and were all spotty.

The gills of the dead ones are pink and mushy.

Fizzy, how much water do you have? How much was left after the overflow? How long do you think it had not been cycling for? With them gulping at the surface, sounds like Oxygen shortage to me? Did the remaining ones perk up when you got some water flowing again? The spots could be just from stress. No fungus etc, and those levels of amm and nitrites would not have contributed IMHO

i think you're right about the DO, and as nitrite inhibits 02 uptake thats going to make it worse.

Ahh, good point Steve, I read that in the nitrites and fish health thread. If nitrites are causing problems, the fish may be hanging around at the water return zone.

It has been less than 24 hours at this level.
1400L normally in tank, probably got down to around 900L maybe more, so there was still quite a bit of water. I estimate that most of the larger fish died, so would have had less than 6kg in total of fish.

Wouldn't say they have perked up at all, but they definitely don't look so bad anymore.

FJ, have you got an aquarium "bubbler/airstone" you could put in the tank to pump lots of O2 into it quickly???.... might help the fish recover quicker

I have a bubbler going 24/7 with DC backup - but the just doesn't blow much anymore.
It started fine, but now the stones are all clogged and output is minimal.

What is a good bubbler that won't clog.

24 hours is a fair while without it, however 6 kg's in 900 litres is not much. if they have stopped dying, you have hopefully turned the corner.

a good burbler that wont stop.... humm that would be a politician or a lawyer wouldn't it lol

or a 5 year old boy

how old were those air stones/???? I have had mine for 2 years and the olny problem I had was that one (out of 6) became brittle and broke...

air stones - less than 3 months.
it has been 6 hours and the remaining fish now look quit active again.
Lets hope it was just low DO.

It just goes to show how tempremental they can be and how much you need to keep an eye on things to make sure everything is working fine.

I think the underlying problem was organic buildup in the drain pipes of the grow beds slowing down the drainage. Thus when filling on a preset timer some were overflowing.

Now I just have to get more fish.

FJ, how big are the drain pipes in the grow beds and are they meshed to prevent solids getting in or was it roots and things that blocked them???

Mate ...

It has been real hot lately, my fish are struggling a little. Dissolved oxygen is a real prob when it gets warm.

I even had to thow some ice in to get the temp down a little,

I would try a small pond pump, and have it filling a small tray positioned over your fish tanks..

(I actually am doing this with one of my wheelie bins.)

Insert pieces of black retic pipe into holes in the base of the tray vertically. The length of the pipe need only be 4 cm or so. Have less than 1 cm of each pipe protruding into the tray.

This creates a little series of vortexes as water leaves the tray and flows into the fish tank. The mixing will dissolve oxygen into the water.

It wont block, and if you are really concerned that the tray will overflow you can always plumb in a large diameter overflow pipe.

I love the sound of splashing water.

OH .. BTW I fished out over 300 fry yesterday.

Johnnie,
I went and bought a small pond pump and attached a sort of fountain, but it get falling over, so I just put an elbow on the top and now have a splashing current running through the tank.

However I do like your idea and would love to see a photo just to make it clearer in my mind.