had several fish die but I am not sure why.

[Steve knight]

my little 160 gal pond had 3 gf die off this week. the water last time I tested 3 weeks ago was perfect. I had just removed 2/3 of the fishload (Koi I bought to tame down the gf) and I only had 5 3-4" gf and minnows. tons of plants as you see in the pictures. 2 weeks ago I put in airstones as when it was hot the fish were hanging by the water return. I just did the usual 20 gal water changed and cleaned the filter (not very dirty) but the problem I had was my mini bog was having low water flow issues. it is a upflow design loaded with pea gravel. the larger plants were a mas of roots and blocking waterflow. H ad lofted them up to see if I could get a better flow. all I can think of is I released something lifting the plants several times. But I never smelled anything and the water was not dirty looking and the roots were so massive I lifted most of the gravel out with them. the water is filtered before it hits the bog.
it was either that or one of the fish died (covered in fuzz earlier this week and that polluted the water and killed the others. with so many plants I did not see the fish floating.
I did not test the water since it had 3 dead fish in it and I am sure would be way off. the water temps have been about 75 max and it is clear but for what the plants leave in it. I have a 600gph pump and a a external laguna filter that does really great on a small pond.
for the last several days the fish had not been coming up to eat I was thinking they were overfed as we were working out how little to feed.

 

[addy1]

Not sure Steve, but my best guess would be the gf died for some reason and fouled the water, which caused the death of the other two.

 

[j.w]

Can too many plants cause a problem w/ oxygen? Seems like there is something about plants giving off oxygen during the day and something else happens at night. Water and weather were not too hot. Like addy said could have been the one dead one that fouled it for the others and your pond is small so it may not take too much to foul it. w/o a fish autopsy you may never know. I've had a fish die for no reason that I knew of and all the others were fine and water was clean etc. Dead fish looked fine too, other than he was dead.

 

[pinon ponder]

So sorry about your fish dying. I would still test the water, just to be sure it's not the cause. At least you could cross it off your list of culprits.

 

[Steve knight]

I had a lot of oxegenators that I have been removing lately because they are overrunning the pond. I planned on testing the water tomorrow. I mean it would be silly to test it with three dead fish floating in it I knew it would test bad. Plus I just did a big water change.

 

[fishin4cars]

The only thing that should change as far as a bad reading from fish dying is ammonia, and nitrite. of course they would be off and high, you expect that, but what about the rest? Ph and Gh and KH all could have dropped and caused the die off, lots of plants use up a lot of the buffering in the water and if that happened the PH can crash. Fish dying will not change that reading one way or the other. So if you know the readings that you took in the past and compared them with what they are now you can at least set a baseline of what if anything is going on with the water. keep in mind in your small pond changes can happen far more quickly. You were higher stocked and this may have been coincidental that it happened right after reducing the load.

 

[sissy]

remember plants give off oxygen during the day and use it up like crazy at night .I always turn my air pump higher at night

 

[Steve knight]

i have the airpump going 24/7
Just checked the water and everything is normal one day after 3 dead fish.

 

[sissy]

Did you check for any shorts in the wiring small electrical shocks could kill fish and you may not even notice it .I had a pump with a bad connection from tetra and I was lucky to find it before anything happened .Now I use harbor frieght cheapy pumps