Pond Boss Forums GENERAL QUESTIONS Help Fish Kill

Wondering why my catfish died, none of my bluegill/sunfish died, had a handful of minnows that died, you can walk around the pond and see small minnows swimming everywhere, the catfish weighed 4 to 10 pounds about 40 or so died, i pulled 2 of them out of the pond that were still alive and put them in a large metal water trough, that is feed fresh water by my windmill, that then flows over into the pond, pond is 1/4 acre in size, the catfish I put in the water trough are fine now. I checked the dissolved oxygen in the pond 12 hours after the fish started dying and it was 6.4, and 10.0 in water trough, I had feed the fish the night before, which I do every late afternoon for the past 7 years. Pond depth is around 5 to 6 feet. I fed last night and the bluegill/sunfish ate along with one catfish that was still alive in the pond. It was a sad sight to see all of my catfish dead.

Usually the big ones go first..

Dissolved O2 starts dropping when the sun goes down, and is lowest before sun-up. Did you check the DO during the middle of the day, or early in the morning? Hotter water holds less DO. Larger fish go first due to higher DO requirements than the smaller fish.

I'm in the same boat it appears. However my situation is a little more involved. I'm in the process of starting a new aeration system. Yesterday, saturday, was my 8 hour day for the system run time. Today should be a 16 hour day if doubling of the time is the recommended process. I lost two large catfish over night, one the day before, four the previous week, and 6 over the previous month. I figured that I needed to get the aeration system up and running quickly in order to stop the catfish kill rate. But am I going too fast? yesterday I ran the system from 2:30pm to 10:30 pm. I started today at 11 am. Should I cut back to 12 hours instead of 16 hours?

The pond is about 1/2 acre in size, with the deepest section at 8' to 9'. The pond is basically two triangles attached by a channel. The largest triangle has an island in the middle. So there are two stations in this pond section one at the deepest 6' section and one across the island in the next deepest 5' section. Then the second triangle with the deepest 8' to9' section has the last aeration station. This section also has a waterfall that comes in the farthest from the deepest aeration station. I have a Vertex HF 3+ XL2 with three stations in the system.

So should I stop running the system start up process? Or should I ramp up the system to full time. The pond has LMB and some type of catfish. There are also mosquito fish and a few large gold fish. I'm not finding any dead LMB or pond whale sized gold fish. What should I do?

Yesterday was a cooler day with temperatures around 70. Last night was cool also with the lows down to 43. It is 73 now and might make it to 80's. This coming week will have temperatures back into the upper 80's. I'm located in Northern Nevada just east of the Sierra's and Lake Tahoe. The water temperatures are in the low 60's.

DLJ - Others should weigh in on this topic. Your situation is more involved and I don't think it is aerator related because your bass are not dying. If the problem is a lack oxygen & too much hydrogen sulfide problems from incorrerctly starting the aeration, why are bass and goldfish not dying unless the others are dead and lying on the bottom and you are not seeing them? IMO, but I have no proof, I think LMB would require slightly more DO before they are stressed compared to catfish.

I don't think your pond would not have a large enough or voluminous anoxic zone to cause the problem you are describing. Sinced you apparently ran the new aerator gradually over the period of a few hours per day before the 8 hr/day compressor run, water quality should have remained low stress. From your description can I assume that your catfish were dying before you started aeration????

Yes the catfish started dying about two months ago, about one per week. Water clarity has been good with coontail plentyfull and not much algae. I know that there are more catfish in the pond for about a month ago I saw about 18 large ones sunning themselves or gasping for air around a clump of coontail at the deepest 9' section of the pond.

I cannot help solve the problem, but my pond experienced a fish kill after prolonged snow on ice cover. My large channel cats were the most heavily effected with the BG, RE, and LMB less effected. I have a recovering fish population but no surviving CC as far as I can tell. I believe that the large CC may be the most sensitive to low DO although I always though they were the least sensitive. Just my experience...

I would set the system for 8 hr run time as you are probably getting a fullturn in that timeframe, I would leave it there for a week and then if nothing adverse add some hours each day. The 8 day startup procedure is just a "guideline" as can be too aggressive for a summer startup. (slow it down)to be safe.

O2 is the lowest right before the sun comes up, so I'd try and have some of the start-up run time during that period if possible.

Thanks. I just checked the pond and after running for 4 hours I was getting a skanky smell. Not sure I'd say sulfur smell, but perhaps. Is that indicative of anything?

Was wondering if I should put the two catfish that didn't die,the ones I put in the water trough back into the pond. There were a couple more catfish that died yesterday, no other minnows/bluegill/sunfish have died. I did use a trash pump that sucked water from out of the pond and sprayed back a 1 1/2 inch stream of water back into the pond, I did that several times. I checked the dissolved oxygen at noon the next day after I started finding the fish dead.

FFF, check the DO first thing in the morning (really , really early) and post your findings.

What are you using to measure it?

Dumb question. How-what do you use to measure DO?

DO 4.32 PH 8.24 sample taken at 7:30AM, I went ahead and put the 2 catfish back in last night not knowing what the DO was, they were on the bank this morning almost dead, I caught one with a dip net and put him back in the water trough, the other one slowly swam off. It has been hot and no wind to turn my windmill, I have a water hose running into the pond now. I used the trash pump to pull water from the pond and pump it back into it hoping to bring the DO back up, but it is not staying up. I think that I have had alot of minnow hatchings, can this be part of the problem with the DO. I have never had this problem in the past, I stocked minnows into the pond about a month ago. Still no other fish have died, no minnows, no bluegill, sunfish, just the catfish, how can other fish live in water that the DO is low in.

Consider that you might have a disease unique to catfish. Or maybe the water quality where the catfish hang-out (deep water) is harming them.

Well I thought I had gotten through the worst with starting up my aeration system. But yesterday I found another dead catfish. I'll post photos and perhaps someone might be able to tell me what species this catfish is, and any guesses on what might have killed it.

Additional photos.

A second catfish has shown up dead. I've been running the aeration system 24/7 for about a month now. I suppose the problem isn't from that. Any thoughts on what may be affecting these catfish?

Have you looked at this from the archives ?

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92438#Post92438

What species do you think this catfish is?

If it has a forked tail it is a channel cat. Unforked is a bullhead.