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Small Tilapia Dying
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Author:  jrchildress [ Jun 29th, '11, 12:56 ]
Post subject:  Small Tilapia Dying
I'm having some of my small tilapia dying. Here's the background. I bought ~150 Nile Tilapia a little over a week ago. I transported them from Arkansas to Central Oklahoma (about 5 to 6 hours). When I go home I had about 8 or 9 that were dead or close to dying. I assume from an ammonia build up in the hauling tank on the trip. These were all very small fish (about 2 inches/5 cm). I had a mix of sizes, from 2 inches (5 cm) up to about 5 or 6 inches (120-140 cm) at the largest. I acclimated the fish and stocked them into my tanks. I have two tanks that are 300 gallon (~1000 L) each. So about 75 fish per tank. I'm assuming this is a relatively low stocking density. Now I seem to be loosing about 1 or 2 fish every day or so. I'm up to about 20 or so dead fish. All dead fish have been the smallest size.

The system had cycled for over a month. I used starter bacteria from a large fish aquarium that I have. I also added some ammonia (human source). The Nitrites and Nitrates had both spiked and were at zero when the fish were stocked. I don't currently have an ammonia test.

The water temps have been in an ideal range. from 75-85 degrees F.

The Nitrites and Nitrates are still running very low.

Oxygen is good. I have aeration to the tank, plus a lot of splash with the inflow.

The pH is kind of high. It is usually about 8.0 to 8.5. Hopefully this will come down as the system ages.

The large fish are eating well. Look healthy. Act healthy.

Any ideas? Could it be the bigger fish beating up on the little ones?
Author:  keith [ Jun 29th, '11, 21:32 ]
Post subject:  Re: Small Tilapia Dying
did you have air when you transported?
the stress of the move may have done them in.. (stress makes them susceptable to problems)
have you salted? salt helps alleviate stress in the fish but use "pure" salt, not iodized or with any anti-caking agents.. salt to 3ppt should help
Author:  jrchildress [ Jun 30th, '11, 08:30 ]
Post subject:  Re: Small Tilapia Dying
Here is the set-up that I used to haul the fish. It did have aeration, but it was about a 6 hour trip.

I've added a little structure (PVC pipes, etc.) to give the small fish some refuge. I'm adding a small de-gassing tower for the incoming water, and I'm converting the standpipes so that they pull water from the bottom of the tank instead of skim off the surface.

I may try the salt as well. I'm guessing that this concentration of salt is O.K. for the plants in the grow beds??

Thanks for the help.

Attachments:
File comment: The fish hauling box
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Author:  keith [ Jun 30th, '11, 09:11 ]
Post subject:  Re: Small Tilapia Dying
3ppt would be a ok for most plants but some are more intolerant.. like cuke's and strawb's
i've never transported that many fish, but the losses could be attributed to the stress of the move.. did you acclimate them to your system? might have been a big ph swing that did in any of the most stressed fish.. looks like you had a couple that were close to kickin the bucket in your transport..
keep an eye on your levels and hold off on feed
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