Pond Boss
Posted By: Weissguy Had a huge Tilapia hatch yesterday - 12/08/09 11:46 PM
I've been working on a white strain of Nile Tilapia for quite a while now. I've been selecting for fast growth and white coloration. One of my breeding colonies produced about 1500 to 2000 fry in a nicely synched spawn, and they became free swimming in the egg tumblers as of yesterday. That spawn was from just 3 young females that average about 7-8 inches in length! The fry are now in a nursery aquarium. I'll try to take some pictures and post them shortly.

I've been selling quite a bit locally for the last several years just to keep from becoming overloaded with fish. By spring, I will have produced over 30,000 fry. Crazy!

Posted By: CJBS2003 Re: Had a huge Tilapia hatch yesterday - 12/09/09 03:28 AM
Can't wait to see the pics...
Posted By: ewest Re: Had a huge Tilapia hatch yesterday - 12/09/09 03:33 AM
SRAC



Reproduction

In all Oreochromis species the male

excavates a nest in the pond bottom

(generally in water shallower than 3

feet) and mates with several females.

After a short mating ritual the

female spawns in the nest (about

two to four eggs per gram of brood

female), the male fertilizes the eggs,

and she then holds and incubates the

eggs in her mouth (buccal cavity)

until they hatch. Fry remain in the

femaleÕs mouth through yolk sac

absorption and often seek refuge in

her mouth for several days after they

begin to feed.



Reproduction is best at water temperatures

higher than 80o F and does

not occur below 68o F. In subtropical

regions with a cool season, the number

of fry produced will decrease

when daily water temperature averages

less than 75o F. After 16- to 20-

day spawning cycles with 1/2-pound

Nile tilapia, fry recovery was about

600 fry per female brooder at a water

temperature of 82o F, but only 250

fry per female at 75o F.
Posted By: Weissguy Re: Had a huge Tilapia hatch yesterday - 12/09/09 09:09 AM
Ewest - It sounds like mine are producing right on par with the results of that trial. I would have virtually zero survival if I didn't strip them and use tumblers though. They nail the fry the second a female releases.

I really need to get a better camera. This one just can't handle macro shots very well. At any rate, here are a few pics. It was difficult getting a lot of them in a shot because the second I would get the camera close to the tank they would scatter. Sorry so many are blurry. I tried manual settings to correct issues, and I still couldn't get it to where I would like. Some look like they have missing or odd tails, but this is just an illusion due to the rapid movement and the slow exposure.

These are 2 day old White Nile Tilapia fry. I linked them rather than include them as embedded images because of their size.

http://cascadestaff.com/kpics/tilapia01.JPG
http://cascadestaff.com/kpics/tilapia02.JPG
http://cascadestaff.com/kpics/tilapia03.JPG
http://cascadestaff.com/kpics/tilapia04.JPG
http://cascadestaff.com/kpics/tilapia05.JPG
http://cascadestaff.com/kpics/tilapia06.JPG
http://cascadestaff.com/kpics/tilapia07.JPG
http://cascadestaff.com/kpics/tilapia08.JPG
http://cascadestaff.com/kpics/tilapia09.JPG
http://cascadestaff.com/kpics/tilapia10.JPG
Posted By: CJBS2003 Re: Had a huge Tilapia hatch yesterday - 12/09/09 01:09 PM
Cool looking fish... How much have you been selling them for?
Posted By: ewest Re: Had a huge Tilapia hatch yesterday - 12/09/09 02:31 PM
Those are not bad pics considering movement and through the glass aspects. Here is a pic I took after trying what you did with way to many fuzz shots.




Posted By: Weissguy Re: Had a huge Tilapia hatch yesterday - 12/09/09 08:40 PM
CJBS2003 - I've been selling them from fry size to about 4 or 5 inches, and I've been asking anywhere from 50 cents to $3 depending on size. One of the area universities is now using my fish in their aquaculture research program, and I recently sold a bunch to a gentleman in Minnesota who is building quite an interesting (BIG) growout setup to deliver live, iced and fillet tilapia to the local markets and maybe a CSA. Kinda cool!

Ewest - I've seen that yoy bg pic several times, and I've always thought it was an excellent macro shot for consumer grade equipment. I'm considering getting a new fancy camera and investing in a nice (unfortunately, expensive) macro lens to go with it. I'd really like to be able to capture some of these types of shots with sharp contrast and fine detail.
Posted By: Blaine Re: Had a huge Tilapia hatch yesterday - 12/10/09 02:47 AM
I had my first hatch 2 weeks ago (my winter experiment). Blue tilapia but I have only seen approx. 25 fry. Shouldn't there be more? The fry are still in the 80 gal tank with 7 adults and holding steady. How important is it to segregate them? Any other advice? I hope I have a larger hatch soon or my experiment will be a bust.
Posted By: Weissguy Re: Had a huge Tilapia hatch yesterday - 12/10/09 03:00 AM
Blaine -
I would seperate them right away. While the adults MIGHT leave them alone, it's more likely they'll eat them or at least most of them.

You really want to try and get all of your females to spawn at about the same time. Fry just a week or two younger in age will be eaten by the older ones. Tilapia are highly cannabalistic until about 8 weeks of age, which means that you'll have to maintain seperate nursery tanks until the young of year are a safe size to mix with each other. It's a real pain if you have females spawning randomly.

There are two things you can try to get them "synched":

1. Strip any females holding eggs in their mouths before beginning. Seperate males and females for about 10-14 days. When you combine the fish again, place on an 18 hour light and 6 hour dark lighting schedule.

2. Control by manipulating the light cycle. Strip any females holding eggs in their mouths before beginning. Prevent any light getting to the fish for 10-14 days only allowing for about 10 minutes a day of light for feeding. Following this, provide light for 18 hours followed by 6 dark and continue the 18L 6D cycle going forward.

It's a lot easier to deal with hundreds of fry/fingerlings that are the same age and size than it is to deal with a few dozen small, a few dozen medium, a few dozen large, etc.

Posted By: Blaine Re: Had a huge Tilapia hatch yesterday - 12/10/09 03:34 AM
What do you mean strip the females holding eggs? Does this mean segregate them from the others? Or do you mean strip them of their eggs? If the eggs are in their mouth, does that mean they are already fertilized? How can you tell if they are holding eggs? I do have one that is bulging under the mouth and is darker colored in that area than the others.

Thanks for all of the info weissguy! you may have saved my whole winter experiment in a single post.
Posted By: Weissguy Re: Had a huge Tilapia hatch yesterday - 12/10/09 04:52 AM
 Originally Posted By: Blaine
What do you mean strip the females holding eggs? Does this mean segregate them from the others? Or do you mean strip them of their eggs?


When I say strip the females of the eggs, I'm talking about removing the eggs from their mouths. Simply net one out that is holding, grab her in one hand the way you would hold a bluegill when removing a hook, then use your other hand to open her mouth, and then dunk her head in and out of the water of a small bucket (while still holding mouth open) with about two inches of water in it. The eggs will come flying out in the water. If you want to keep the eggs and try to hatch them, build or buy an egg tumbler. Just keep in mind, most of the ones I see for sale tend to have screens that are too big for tilapia eggs, so you may have to replace those screens. I tumble pretty much all of my eggs. It's important to note that tilapia eggs are extremely prone to fungus, and you can lose an entire tumbler full of eggs in less than 12 hours if just one egg gets fungus and it spreads! I've had it happen many times, and it's a real let down. The truth is, the fish do a way better job at tumbling their own eggs than an artifical tumbler does. To try my best to combat fungus, I place my tumblers in a dedicated hatching aquarium (no fish) with seriously overkill filtration and aeration. Crystal clear, oxygen rich water is a must. Some people treat eggs with methyl blue to reduce fungus risk. I have not, but it might be a good idea.

 Originally Posted By: Blaine
If the eggs are in their mouth, does that mean they are already fertilized?


The eggs in her mouth should technically be fertilized. However, sometimes a female gets too anxious to collect them, and they don't get fertilized before she grabs them all. They'll carry around dead eggs sometimes for up to a week before they realize they aren't going to hatch. The point is, if they are in her mouth, the opportunity for the male to do his part has passed, fertilized or not.

 Originally Posted By: Blaine
How can you tell if they are holding eggs? I do have one that is bulging under the mouth and is darker colored in that area than the others.


It sounds like your female is indeed holding. When they are holding, they don't eat, tend to keep their mouth almost entirely closed and have that bulge under the mouth like you describe. Often times the females will get darker colored as well.

 Originally Posted By: Blaine
Thanks for all of the info weissguy! you may have saved my whole winter experiment in a single post.


No problem. Glad to help!

Posted By: Rainman Re: Had a huge Tilapia hatch yesterday - 12/10/09 10:51 AM
I've built several tumblers but found them to not really be needed. I either wait 10 days from when the females are holding eggs and harvest the fry or I harvest the eggs and put them in a jar with a small ball shaped airstone. The females "tumble" the eggs secondary to passing oxygenated water over them- not because the need movement. I can get 100% hatches by using ceramic oxygen diffusers with all eggs sitting nearly motionless in bunches or even in netting setting in a brood tank.


Kellen, if the guy in Minnesota bought several hundred from you about 4-6 weeks ago, it may be a guy that I suggested call ya.
Posted By: Weissguy Re: Had a huge Tilapia hatch yesterday - 12/11/09 01:30 AM
Rex -
I agree. Oxygen rich water is the single most important thing. Before I started stripping eggs, I actually had a good sized batch of them hatch just sitting in the gravel of one of my tanks. The female spit them out about 5 days early. I left the eggs in there thinking for sure she'd go back and gather them up. She didn't of course, but I lucked out anyway.

I tend to strip eggs within 1-3 days following a spawn. It puts the female back on food quicker and results in a faster follow up spawn too. Truth be told, most people who use tumblers move the eggs around far too aggressively. I'm convinced just a little movement is good, just to help get fresh water around the eggs to help prevent fungus issues, but I really have no data or research to back that up beyond my own observations. I shake my head when I watch a bunch of the egg tumbler "how to's" on youtube. The eggs look like they are in a Lotto ball machine, shooting around all over the place.

Rex - Guy's name in MN is Mike, if that rings a bell. Real nice guy. Thanks if you sent him my way!
Posted By: Weissguy Re: Had a huge Tilapia hatch yesterday - 01/19/10 11:46 PM
Blaine -
What's the update on your "winter experiment"?
Posted By: Blaine Re: Had a huge Tilapia hatch yesterday - 01/20/10 09:24 PM
Hello Weissguy,

Unfortunately all but two of my fingerlings have been eaten. I guess it wasn't a total loss, just a very poor and expensive first attempt. I never did break down and buy the second tank. I think about following your advice on spawn promotion all of the time but haven't invested in the additional equipment that that I need. If I don't do something soon I won't have the larger sized fish that I want in the Spring.
Posted By: Weissguy Re: Had a huge Tilapia hatch yesterday - 01/20/10 10:37 PM
Yea, you definitely need to invest in an additional tank. Have you checked out craigslist? I'm picking up a 55 gal with hood, heater, filter, air pump and stand for $35 tomorrow. Best deal yet. Normally I get just the tank and hood for $40-50. I've got 5 55 gal tanks already and the total cost for all of them has been right around $200. I find smaller ones (10's and 20's) for free quite often, but I have more than I can handle of those at the moment as it is.

Just to give you an idea, I've currently got 900 1 inch fingerlings in a single 55 gal tank, 700 2 week old fry in a 20 gal long, 300 2 inch fingerlings in another 55 gal, 30 3 inch fingerlings in a 29 gal and 45 5 inchers in a 45 gal hex. I also have another batch of about 500 fry getting ready to turn into "swim up" fry in my hatching jars.

If you can get a workable system going asap, you'll have no shortage of fish by springtime.

Posted By: Blaine Re: Had a huge Tilapia hatch yesterday - 01/21/10 04:26 PM
After a spawn, do you remove the adults from the fry? Or do you try to fish around with a fine net to capture 100's of tiny fry?
Posted By: Weissguy Re: Had a huge Tilapia hatch yesterday - 01/21/10 07:58 PM
I strip the eggs from the female's mouth 2-3 days after spawn, clean them and place them in a hatching jar. Egg tumblers work well too. About 5 days later, they begin to hatch. Once the hatch has completed, I transfer the fry into a nursery tank and begin feeding.

I don't typically allow the adults to hatch their own because of the risk of the adults eating them right away when the female releases the fry. Plus, netting out hundreds of fry while the adults are going nuts because of the presence of a fish net becomes a wet, nasty and frustrating venture. However, I am hatching 1000's of fry at a time usually. On a smaller scale, you could probably let the females hatch them on their own and get the results you're seeking. You just have to be ready to scoop fry out the second the female releases, OR strip the fry from the female at about day 6 and place them in one of those fry cages you can buy cheap at a pet store. Just make sure to be VERY careful when trying to capture the female. If she gets too nervous, she'll spit the eggs/fry out, and you could have a total loss if you are unable to collect them.


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