Dead Fish Question

[LPMurphy]

I had floater yesterday am and another today. My system is not covered yet and we got hard rain two days ago if that matters. My water was clearer yesterday and even more today. I can see the fish at the bottom of the tank now. You can see those prior pea soup pics at the bottom of
http://www.aquaponicshq.com/forums/s...4412#post14412

Is there anything the condition of this dead fish can tell about the problem (please other than the fact that it is no longer respirating). Is there anything else I can see if I disect it that will tell me?
You can see some redness around the gills, the black spot on the chest and I am not sure if the green just past and below the gills is normal.
I've added white distilled vinegar in 118l increments on the 26th and 27th for Ph - will add another today.
Water Stats
PH - 7.4
Ammonia - <.25
Nitrite - <.5
Nitrate - Between 80-160

[Castaway]

I would go straight to an Aquarium/Pet Shop and buy a good aerator with say a 4 hose outlet, some plastic tubing and some air stones and I would oxygenate that green fish tank you have 24/7. I could be wrong here - but apart from pH concerns, I suspect lack of dissolved oxygen is what killed your fish. A little splashing water from the Grow Bed return pipes may not be enough to oxygenate your fish tank sufficiently and keep those fish alive. The cost of running a 10 watt aerator is minimal costing only cents over the course of a year. If you can also get some current flow from the return pipes say three return pipes angled to create a water swirl effect so the fish have some current flow (imitating nature) to swim against you'll find that they'll perk up a bit. Good Luck but do get some air into your fish tank.

[Murray]

I suspect lack of air and water movement to be the main problem.
As Castaway says, get that water moving and plenty of it. Loads of air going into the system with the tank covered from the sunlight and ingress of rain.

The pH is a bit high, but nothing to worry about....It would not cause the deaths at that level. (due to ammonia toxicity)

[fishfood]

Thay also look skinny like they are not eating [ i bet theres nothing in there belly]

[LPMurphy]

Thank you to all for the input - it is truly appreciated.
Interesting observation Fishfood. I cut one open and no there was not any food in it's belly. If it floated close to the time it died it had been about 20 hours since feeding - not sure if there still would have been food there anyway. However, I had been weary of overfeeding and hand feeding them enough to last till they were through with the frenzy and acted picky (took about 15mins).
I experimented and went back and fed again in a couple of hours to see how they acted and they went at it again. Next night I fed double what I had been and they took it all.
I suspect a combination of both underfeeding and DO - especially considering I am feeding at night where the algae in the water is sucking up the DO at night. They just would not eat during the day when I tried.
I do have my system setup to push 1135l of water from the sump into the 1325l FT every two hours. It takes 13 mins for the pump I am using and I get a lot of movement and spray doing it - probably what has kept me from disaster for now.

[Murray]

setup to push 1135l of water from the sump into the 1325l FT every two hours.

At the end of the two hour gap when there is no water movement the DO will be greatly diminished. It does not take long for the oxygen in the water to be used up by the fish. It is better to have water movement all the time or at least in much shorter cycles.
Some fish in any given school of fish, are at the bottom of the pecking-order and just do not get to eat.

[aussieap]

you need the water in your fish tank changing over once every hour to keep DO up, even at non commercial stocking densities.

[GaryD]

.....and I'd suggest that you run a separate air pump anyway. It's cheap insurance.

Gary

[LPMurphy]

you need the water in your fish tank changing over once every hour to keep DO up, even at non commercial stocking densities.

This begs another question. It takes 13mins for my pump to push all the sump into the FT. Have not timed how long it takes to dump all of it into the growbeds - maybe another 10-15 mins- but it takes about an hour to fully drain the beds.
What kind of timing are ya'll doing for flood and drain for the beds?

[Murray]

On my old Homestead kit the cycle was 10 minutes to pump the beds full and 40 minutes for them to drain.
Now that all of our systems are CHOP the cycle is around 12 to 15 minutes.
I notice in high summer the shorter cycled systems did better. There was no wilting between cycles as there was on our really hot 38 to 40 deg days in the old flood and drain 50 minute cycle system.