Comment

Comment by Michael Welber on March 30, 2012 at 8:57am

So many factors. pH is OK and I'm using cistern water so pollutants "shouldn't" be an issue but who knows these days. We live in an area where there is no agriculture and they haven't started spraying for mosquitoes yet. Temperature is fine; the water is about 75 degrees. I did add some water to the tank yesterday so that "could" be the reason. The water was a little colder and the pH might have been a little different but not significantly. 

The water is brown and not clear. I wonder if I should change out 1/3? Problem is, if I do that then the changes of water will be exacerbated.

TCLynx: I had thought it was as much as they could eat in 5 minutes. Is 15 more reasonable? 

Comment by Sheri Schmeckpeper on March 30, 2012 at 8:50am

What I've observed with ours is if you feed enough, the aggressive ones fill their bellies and the remaining food will eventually be eaten by the smaller fish, usually after it sinks. I think our smaller ones survive on algae as well.

Other factors might be aeration, PH (but you said that was OK); possible pollutants like insecticides, even natural ones, and leaching; and temperature. If all that pans out, do you think there might be something that changed in the source water?

Comment by TCLynx on March 30, 2012 at 8:47am

Michael, are you able to feed as much as they will eat in 15 minutes without having water quality issues?  If so, perhaps you can spread it around and feed a lot at once to see if the little guys get a chance to get to the feed without the big guys getting it all.

And sometimes the runts are not all that robust and it isn't uncommon to loose a few, though 6 out of 50 seem more than enough losses unless you got a lot of genetic rejects.

Comment by Michael Welber on March 30, 2012 at 8:37am

Thanks Sheri. Yes, the numbers are all OK. It was a floater as were the others. The fish range in size from that of this one, rather small, to others that are about 4 inches or so. I started with 50 fish and 6 have died. They are in a 300 gallon tank. The large fish all seem fine, eating with gusto. I have been concerned that the small fish aren't getting enough food with the big ones eating all of it. I have been feeding with a couple of different sizes of food because of that concern. 

Comment by Sheri Schmeckpeper on March 30, 2012 at 8:25am

MIchael, I assume you've checked all your measurements? Ammonia, nitrites, nitrates & PH?

Your dead fish might just be due to territorial issues. Were these floaters or did they jump out? If you have mature/maturing tilapia, the bigger ones will get territorial and chase the smaller ones, sometimes incessantly. Smaller fish will even jump out when they're running from the perpetrator unless there's a cover. They won't have injuries in most cases. How many fish do you have /gal of water? And what is the size range of your fish?

Comment by TCLynx on March 30, 2012 at 7:53am

Yep, kiddie pools sometimes work and sometimes at your own risk.  Now if it is just a small backyard thing and not many fish at risk, then it isn't that big a risk.  But if talking about going for a commercial scale operation, perhaps maybe getting something that some one can definitively say is fish safe is the option I would probably recommend and hence the recommendation of looking at Aquatic Eco systems for the Fish safe Pool.

Comment by Larry Reinhardt on March 30, 2012 at 4:34am

I guess not all pools are created equal, last year I used two Intex pools from June till August to hold my young catfish and tilapia. Bought the pools from Kmart the 1000 gal for 6 weeks then a 3000 gal till the middle of August. I had no problem at all, perhaps it was because I used a lot of air to drive 4 big sponge filters. I also setup 3 of those 8' fifteen dollar ones from Walmart to raise my guppies and killie fish in and they were safe as well. However I used a large plastic garbage can as a filter for 500 gal pool made of 2" X 12" lumber lined with black plastic sheeting and that killed some fish so I replaced the garbage can with a black tote tub for the filter and all was well. I put a few guppies in a new pool to test it, if they live a day or so then its alright to use. Over the course of my 60 years raising fish as a hobbyist and commercial fish farmer I've used dozens and dozens of above ground pools without any bad happenings, of course there could be a first time just around the corner. 

Comment by Raychel A Watkins on March 30, 2012 at 1:34am

T C I am one of those people who used a kids pool.  Intex was the brand.  I had used one that had been used as a swimming pool.  Because it had been used for awhile it was no longer toxic,  I was doing aquaculture at the time,  I decided to set up another one but I only put a few fish in it.  It killed them quickly.  I had another friend that killed 2000 baby asian catfish at the same time.  Thwy are not safe unless they have been up and used for awhile.  I suppose aquatic Eco uses onse that don't have anything in them

Comment by Michael Welber on March 29, 2012 at 4:12pm

Thanks for your comment Jon but I'm not using heaters. I live in South Florida (the Keys) and our ambient air temperatures have been in the 70s and 80s. The water has been holding steady in the mid 70s. I just checked the pH and it's fine. Here's a photo of the last one. 

Comment by Jon Parr on March 29, 2012 at 4:06pm

SW, glad I could help. I have not discouraged midge flies, and they are somehow subsiding on their own. Still present in all stages of growth, but not the swarms I had, don't know why.

Michael, if your water chemistry is right, temps good, and no visible lesions on dead fish, then the likely cause is metal toxicity, perhaps copper or zinc. And the most likely source of the metal is an electric heating element. Heaters should be glass only, IMO, though titanium and stainless steel are safe too. I've not tried stainless, but my titanium heaters grow a hard bubble-filled growth like coral, that needs to be chipped off periodically or the element will burn. Glass is best, or using a heat exchanger like PEX.

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