[dietribo]

I have a pond that is about 1400 gals, plus an above ground 150(?) gal pond that gets water from the big pond and via a waterfall puts it back into the big pond. I have a large water lily plant in that pond. Besides that I have 3 large tubs again fed by pumps from the large pond that have plants in them and water fall back into the large pond. I have a 1200 and 950 gal pumps feeding two of the tubs and two smaller pumps feeding the other pond and the other tub.
I raised 7 koi from a couple inches each to almost 2 feet each over the past 10-15 years until the above ground pond had a problem and over flowed all the water out of the big pond where all the fish were. I was devastated and did not get any more fish for quite awhile. In the mean time the pond which I filled back up, started getting a lot of hairy algae.
When I finally decided to get more fish, they would either disappear or die but it would usually take a good amount of time. Lately, I have been wanting to do some aquaponics and got about 20 baby talapia. I might add I got 6 or7 Koi from a Koi breeder and also some mosquito fish. The mosquito fish seem to be growing and growing in numbers. The Koi eventually all died. After that I tried the talapia and they seemed fine for a week or so and then I started to find one or two dead fish floating each day.
I did all the tests on the water, PH etc. and that doesn't seem to be the problem. I got some cheap gold fish from a pet store and they seemed to be doing fine, swimming around near the surface in schools. After about maybe a week they all started swimming near the bottom. From that point I would find one or 2 dead floating on the top each day.
I tried emptying and replacing a good amount of the water and getting new fish but the same thing happened. I at one point got 4 algae eaters but that didn't seem to help the algae problem.
After all of this my question is do I need to drain all the ponds and tubs, get the mosquito fish out, clean the sides and bottom and start fresh or is there something else I can do?
If anyone can help I would really appreciate it. Thanks.

 

[Cory1990]

So you just replaced the whole pond water before you started just putting fish in? I'm trying to understand this.

When starting a pond it's vary hard to get anything in there to live and with such a huge body of water it's pretty difficult to cycle the water and get the right living bacteria into the water.

 

[emc7]

filter or no? You have aeration from the waterfalls. You have the same set up as before, but now fish die. Could be temp, lack of oxygen (due to heat or algae) or something toxic (runoff from lawn, poison algae, aerial mosquito spraying)

Have you run a net or something along the bottom? Could there be a lot of dead stuff (plant, fish, bird) slowing fouling the water. In this case a full drain, cleaning and backflush of any filter would be the way to go.

Do you have fewer plants than you did before? Any other changes? New liner?

Did it fill with rain or tap water? If you fill it,you may have to dechlor.

I agree that fish will keep dying if you don't fix what ever the issue is.

 

[Cory1990]

Yea you may need declorinator, emc7 I completely forgot about that one.

 

[TheOldSalt]

Lose the mosquitofish, too. They're vicious killers of other fish.

 

[dietribo]

No I took about 3/4 of the water out. I'm thinking I should empty the whole pond and clean out the hair algae. I have a feeling that has something to do with my problem. As I said i had a great balance for years and years but when the fish died I let the pond run without fish and a lot of algae grew. I scooped as much as I could out with a big net but there seems to still a lot clinging to the walls.

 

[dietribo]

Those little Mosquito fish can kill larger fish like Koi or goldfish?

 

[dietribo]

Answers to above post by EMC7
filter or no?
I have home made filters placed in front of the pump intake. The consist of a plastic box with filter material and volcanic rocks the water has to run through before it goes into to the above pool pond or buckets. There are 2 very large plants in the pond and one of the buckets. i had been doing some raft aquaponics in 2 of the buckets with about 6 plants per bucket but I could never get enough fish going to support the plants.

You have aeration from the waterfalls. You have the same set up as before, but now fish die. Could be temp, lack of oxygen (due to heat or algae) or something toxic (runoff from lawn, poison algae, aerial mosquito spraying)
Since everything except the algae is the same as before ( the big koi pretty much kept the algae down before) I'm wondering if it could be the algae eating the oxygen.

Do you know what would account for the fish first hanging out near the top of the pond and then all of them hang out at the bottom then slowly die?

Have you run a net or something along the bottom? Could there be a lot of dead stuff (plant, fish, bird) slowing fouling the water. In this case a full drain, cleaning and backflush of any filter would be the way to go.

I do every week or so run my big net along the bottom and collect some stuff...Mostly algae.

Do you have fewer plants than you did before? Any other changes? New liner?

As I said above, Added more plants but made no other changes.

Did it fill with rain or tap water? If you fill it,you may have to dechlor.

I use soft water from our well to fill the pond. It also gets a good amount of rain as we live in Florida.

I agree that fish will keep dying if you don't fix what ever the issue is.

So what do you think is the best course of action? Empty - Clean - and refill?

 

[dietribo]

Those little Mosquito fish can kill larger fish like Koi or goldfish?

 

[Cory1990]

Hmm I thought you were going to be one of them guys who makes 2 posts and never comes back.

Anyways just keep goldfish in there. Ponds can be vary beautiful. Have you done anything to it yet and added a declorinator to the water?