High protein feed makes a difference

[TCLynx]

I've gotten myself a bag of higher protein feed for the fingerlings I've moved into the 300 gallon system. Dang, had to adjust the feeder down due to an ammonia spike from the only newly cycled system.

Higher protein feed does cost more but it can definitely make a difference in the growth of small fingerlings as well as increasing the nutrient levels in a system quite noticeably.

[TCLynx]

Michelle, I'm not an expert and there are always chances of developing new methods. However, if you are going to try growing algae in a recirculating aquaculture/aquaponics situation, you are taking a risk. I would highly advise investing in a DO sensor with an alarm and whatever calibration solutions/tools are needed to keep it maintained.

In most third world countries they do green water culture in extensive (big) ponds, these usually are not recirculating and definitely not stocked as heavily as aquaculture tanks are. Even so, they can crash and kill all the fish too. But they add fertilizer of some sort (urea or manure) to cause the algae to bloom to feed the fish. They monitor the thickness of the algae bloom by how far down in the water they can read a chart sort of disk. If the algae gets too heavy they risk all the DO being used up and that can cause a big algae die off as well as a fish kill and the dead algae decomposing in the bottom of the pond also poses a risk to the pond as well.

If you have everything covered and protected from sun, it probably won't grow lots of algae. This is probably better since you want the nutrients to grow the veggies and the veggies will grow better if the pH is more stable.

[Michelle Silva]

Thanks for your reply. Are you sure they don't work? I am concerned about swings at night too, but had asked about them because someone who said he consults on systems has told me to do it, that they work and that they have done these in third world countries. Seems risky. I'm still going ahead without the filters for now, but the way the new set up is I can easily add netting to the tank that has the pump in it. I had planned to cover everything (raft tanks and fish tanks) so not sure if it would even be a "green water system". ~Michelle

[TCLynx]

Beware the green water. I know many tilapia growers doing extensive pond culture will induce algae blooms to feed tilapia. Even in extensive pond culture this requires very careful monitoring and management as well as supplemental aeration or one risks complete fish kills. Green water really doesn't work in recirculating aquaculture and is even more problematic for Aquaponics. Algae will cause major diurnal pH swings (I had three little tubs with some string algae growing, caused my BIG system to have pH swings from 7.5 at dawn and it would have been much lower except that my system is full of shells to 8.8 in the late afternoon.) Algae can also leave your fish, plants and bacteria without any dissolved oxygen left in the water by dawn. Also the dieing algae adds a huge bio-load to the system that the bio-filter has to deal with and any bio-load needs more dissolved oxygen in the water. Basically, too much algae could crash a system and possibly leave all fish dead come sun up if anything goes wrong.

If you want to experiment with green water, do lots and lots of research into it and the specific ways in which people deal with it and also get a dissolved oxygen sensor that you can hook to an alarm so that if the dissolved oxygen drops too low, you can rush out at 4 am and make arrangements to save all the living things in your system from dieing before dawn.

Also keep in mind that the algae is likely to use up most of the nutrients you are wanting to grow your veggies.

[Michelle Silva]

HI Raychel, OK I just ask in another area of the forum what you are feeding your fish and just found this post. I was thinking I could just supplement (if I did green water) with some catfish feed and was also planning on feeding them some of the chopped lettuce too. I read that they convert the alage into protein. Since I have so much compost I was considering creating a simple BSF container out of a garbage can. I learned how in a permaculture class I took. Thanks. Michelle

[TCLynx]

I've been using AquaMax from Purina Mills
My normal feed for the fish once they have gotten bigger is the AquaMax 4000 Dense culture feed which is appropriate for catfish and tilapia to finish growing out with 36% protein I think.
I just lately got a bag of the AquaMax 400 which is a grower feed with 46% protein and much smaller pellets. This is a good feed for small fingerlings for fast growth but it does definitely increase the ammonia levels in a heavily stocked tank so amount being feed needs to be carefully watched till the bio-filter catches up.

[Raychel A Watkins]

ALOHA TC
Whst type food were you feeding your fish. I have always bought my food as I am not sure what would be an adequate food source to get them to grow fast. I think the protein content is 45%. It is generally known as catfish food but all the aquaculture people feed it to all the fish types. I do feed one tank extra duckweed. I always tell them that it is their desert. They seem to like it. I also feed the old bolted lettuce to them. That tank is the only tank that will eat. it. Probably because I started them off on it. I have to say that the little fry that I have been collected for a few weeks love to eat. I grind the big fish food in a coffee grinder and feed that plus some flakes. They seem to want to eat all the time. I keep them in the house because I love watching them grow.
The termites you had a problem with. They must have been ground termites right? Here in Hawaii we have both ground and flying termites. I don't think I have any ground termites. They say they can eat your house in a month. So far the termites have not invaded my wood troughs on the ground. I am making all my beds out of wood with a vinyl liner but now I put them up 30 in off the ground. I hate to bend over. I had my carpenter make me 2, 24 ft long by 22 in wide and 10 in deep. We just put the liner in the second one today.. I hope to hook up the first one tommorrow. I got 600 new tilipia about a week ago. They are beautiful. I am not sure what type they are. They are gold with black spots on them. The guy who sold them said they were rainbow tilapia but he said others called them koilapia. I just know I like them. He said they grow faster than the gold tilipia. We shall see. The problem is none of these people know the scientific name for the species they have.