Aquaculture
2/1/15 - Aquaculture
Over the past year or so I’ve been working on fish breeding and rearing experimentation. One of the very cool things about Blue Tilapia (Oreochromis aureus) is that they are mouth brooders. During the breeding ritual the female lays her eggs on the bottom, then picks them up in her mouth after they are fertilized by the male. She then keeps the eggs and fry in her mouth for the next 14 days or so before letting the fry (baby fish) swim free. It is during this time that females will often sit in a safe place (I have PVC pipes stacked for them to hide in) and incubate her eggs until hatching. To capture the eggs I catch all the female fish one by one and check them for eggs. If they have eggs I simply hold the bottom lip open and move the whole fish back and forth in a pail with water in it. I collect as many eggs as I can and then put them into a small container (yogurt cup) and inline it in my water flow. I direct a light flow of water over the eggs to keep them oxygenated and provide small food for the newly hatching fry. It takes a few days for the fry to absorb the yoke sack and then they look like little swimming eyeballs with tails. lol
Here’s a video of the hatching process...
As the fry grow they begin swimming and eventually find their way out of the hatching cup and into the rearing trough...
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Tilapia are doing extremely well although they have shown highly variable growth rates. Some of them are well over 5 inches and very robust (i.e. fat) while some are still only 1.5 inches or so. They seem to eat almost anything I throw in there including goldenberry plant leaves and strawberries. During feeding time they really go to town on their fish food and today I noticed that some of the larger ones are beginning to display more territorial behavior which could be a sign that they are ready to begin breeding.
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11/13/12
I’m still not finding any nitrogen in the water. Tests always come back at 0 ppm. I think I have more than enough filtration for what I'm putting into it with regards to fish food and the infrequent feeding schedule. I'm in the process of building an automated feeding system so they can be fed more consistently, especially now that they are getting larger. pH and TDS (total dissolved solids) are still about the same at 8.0 and 270ppm, respectively.
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9/10/12 - Aquaculture
The fish tanks are surprisingly very clean!
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8/24/12 - Aquaculture
Fish are eating well. Here’s a short video of the action...
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8/18/12
That appears to have leveled it out in terms of aggressive behavior.
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8/17/12
8/3/12
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8/1/12
Fish Tanks have been running for the past 6 weeks or so. Seem to be holding up well with only an occasion leak when the water gets up near the top. I picked up a few tin foil barbs and a couple of gourami’s from the local pet store to get the nitrogen cycle started. The nitrogen cycle is a critical part of an aquaponics system as it is the conversion process from wastes of the fish to nutrients for the plants. The idea of “cycling the system” is to try to quickly establish a population of microbes within the filter system to handle the waste conversion process so as to stress the fish as little as possible with the more toxic chemicals (namely ammonia and nitrite). Typically aquariums are “cycled” by adding some very tolerant fish for the first month or two while the bacteria levels establish themselves. Here is a chart showing what a typical concentration curve looks like during the cycling process.
The pH for the system has been around 7.5 to 7.8 which is a bit higher than I’d like for the plants so I’m researching natural methods to reduce the pH. One idea is to create a flow-through peat component that will help lower the pH as well as release some natural growth stimulators, namely humic acid and fulvic acid. I used peat extracts of both of these plant growth stimulators in my Master’s research thesis involving phytoremediation (using plants to remove heavy metals from soil for environmental reclamation.
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6/9/12
I had to re-line one of the tanks as I messed up on the folds somehow and it would have leaked but this worked out for the best anyway as I had to drill into the sides of the tank to connect them together with PVC.
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4/17/12
I got the tanks installed and lined this past weekend (April 14-15) … They turned out nice, but whether they work well or not remains to be seen as these are experimental and most tanks of this nature that I have seen are made with EPDM rubber. I used HDPE (High Density PolyEthylene) tarps that are food safe and fairly strong so they should work as long as I don’t jab them with sharp objects! My cat knocked one of the quartz crystals off of the fountain and into the deepest tank puncturing it already so I’ll have to patch it. Hopefully the patch will hold!
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