Woke up to dead fish.

[cptmonty]

All, I need help. I am new to ponding and have my pond that has been up and running for the past 6 months. The pond is 15' x 12' x 3'. The pond has a 3" bottom drain that is piped to a home made skippy filter in a rubbermaid tub 30 gallon that has a pump that returns to the top of the waterfall. I also have a skimmer that returns water to the top of the waterfall.

We live in Orlando FL and it has been hot and humid. We have been loosing a small amount of water weekly to evaporation and topped the water off on monday night. This added about 15% of the water volume.

Last night when I fed the fish all was fine and I had a total of 7 KOI that were 7-8" in length. This morning, I went out and found only 1 fish left in the pond, 3 were dead in the skimmer box and had lost thier colors and 3 were missing.

I justed tested the water and everything seems fine. I use two diffrent test strips the first checks Ammonia and the other does Nitrate, Nitrite, Hardness, PH, ALK, alkalinity.

The only koi that is left is around 10" and he is swimming and breathing fine but we are extremly upset and sad at the loss and worried about him too.

Anyone have any ideas on what may have caused this? Thanks in advance.

 

[koiguy1969]

i gotta take a guess and say you were visted by a preditor and some got eaten some made their way in the skimmer in an effort to evade preditor only to parish there...best guess a heron!

 

[cptmonty]

Thanks for your quick reply.

When my wife first called me, I thought that it was a preditor too. We have seen a few hawks but for 6 months we have had no issues. The skimmer box is oversized and has large area for debris to catch and then some filters before it gets to the back chamber where the pump is. When we first got a single KOI 6 months ago he liked to hide in the skimmer all the time and we had to keep chasing him out. When we bought 2 more fish he decided it was fine to hang out with them and he quit hiding in the filter.

The 3 dead koi in the filter box this morning had no marks or scratches on them but had lost thier color. I have seen where koi die and thier eyes buldge out but these were not that way.

I then thought it was water issues (loss of color) and maybe they were floating at the top and then a bird or racoon got them and thats why a few were missing. I am going to run out and buy a net to protect that last koi left in case you are right. If there is any good news here, the one that is left was my best one and my fav.

 

[koikeepr]

loss of color is not something to go by, as fish naturally turn pallid when they die.

When you tested your water everything was ok? What exactly were your parameters for all the tests, please.

Is it possible fish got caught in the skimmer and couldn't get out? Is it easy for them to get out? If not, they could have been stressed being in the skimmer, which can certainly cause death.

For the size pond you are describing, a 30 gallon filter is too small in my opinion. You've got about 3,500 gallons, and the rule is one 55 gallon barrel/tub per every 1,500 gallons of pond. You would need a minimum of 2 barrels, in your case.

How often do you do water changes? Also, when you do do water changes, do you dechlorinate your water?

This is a mystery...

 

[DoDad]

What is your kh.and ph readings?

 

[nc0gnet0]

While you can never have too much filtration, for his fish load I don't think his filter was the problem.

A predator is a possibility, but........ (Although they may have carried away the dead/dieing ones)

Along with your PH and amonia/nitrite readings (btw get a liquid test kit, strips and highly inaccurate) what are your temp readings?

Is your pond heavily panted? An additional sources of aeration other than your waterfall?

I suspect either a PH crash or a low 02 level that occured overnight.

 

[nc0gnet0]

*Ph crash or elevation I meant to say.....

Seems to me a night time predator would cause the fish to go deep, not come up to the skimmer.....unless they had a total lack of cover..............

 

[koiguy1969]

go see your fish when they are seriously spooked...they even know you and will scatter in all directions full speed bouncing off of things in the pond and eachother.. at a foot long i watched my fish slam into everything in the pond and try to cram themselves into the cracks and spaces inbetween my border rocks. jump out of the water and hit the deep too.this after scaring off a heron..when theyre scared there is NO SET PATTERN of behavior..you have to experience it to believe it!! this irradic behavior can go on for days. and this is coming from someone whos fish will normally swim right to my hands.

 

[koikeepr]

It's so true Koiguy! And if they try to cram into the skimmer to escape--even worse!

 

[koiguy1969]

that skimmer inlet hole looks like a cave to them. especially in a panic.

 

[DrCase]

It is a little strange it all hap pend during the night..
when a heron would be roosting..
A few pics of the pond and cover the Koi had or lack of would be nice
The missing Koi would say predator...

 

[koikeepr]

i really don't think it's a predator based on the descrip. Also he said there were no wounds and the fish were in the skimmer.

 

[koiguy1969]

i dont know .7 fish ... 3 gone ...3 in skimmer... only 1 still in pond (probably managed to hide in pond ) apparently herons are very accurate, i lost about a dozen fish to one in 2 visits and none of the others had a scratch on them. and every vist was at or before sunrise.

 

[nc0gnet0]

I am guessing the missing fish aren't missing at all, somewhere on the bottom in amongst some plants. Hopefully still alive......

A predator is a possibility, just not the most likely scenario.........

Sounds more like an 02 depletion and or ph issue/swing had the fish gasping for air at the surface in a weak state and conversly got sucked into the skimmer.

3 dead in the skimmer suggests something was wrong prior to them getting pulled in, otherwise at least one of them should still be alive albeit in the skimmer..........remember one of the koi used to hide in there and suvived.

And yes I have seen spooked fish before act as you describe, however this predator would have to had remained at the surface for some time to capture 3 fish. Up to this point no herons have ever been sighted......Night time suggest a coon not a heron if it were indeed a predator........it's a possibility, but is it the most likely scenario?

 

[koiguy1969]

if a raccoon visits your pond theres usually little question about it..they tend to leave a large mess. they will dump planters knock over rocks and whatever else is in their way . and a heron got 8 fish in one visit from my pond.. no mess just missing fish. and all visits were at daybreak (still pretty dark). and 7 fish under 8"in over 4000 gallons that has circulation and filtration not much chance of low oxygen