aquaculture: updates?

[tsicar]

any updates on your catfish rearing venture, mellow?

[mellow]

All seems to be working fine so far. The fish are growing, I am feeding them to saturation as you suggested ( easier then weighing out food). We should have time today to grade out another tank. We have been making screen covers ( green plastic screen material) for the tanks to protect the fish from jumping out as well as any predators. Have been doing water changes daily after rinsing out filter tanks. Filling the the filter tanks is about a 6 or7% water change. We should be adding about 10,000 fish to the system this month. Stopped updating because of the lack of participation on the thread.

[Propagator]

Stopped updating because of the lack of participation on the thread.

Don't do that, it is all very interesting, although I cannot make any constuctive comment as know nowt about fish farming.

[Deris]

We may be lazy typists but we like to read.

[tsicar]

We may be lazy typists but we like to read.

agreed.
i have been too busy sorting out my ant problem today, but have meant to post on this thread for a while now.
mellow, don't bother to size grade now. this should be done at an earlier stage. rather carry on as you were, then throw out or sell the non performers at the stage where about two thirds of your fish are sale-ready. the thais will buy fish as small as 100g and even smaller; just don't make the mistake of trying to feed them for another growth cycle.
at this point, stressing them with excessive handling could get them weakened to the point where they can pick up diseases.
as they are feeding well, handling can put them off the feed for a while, too.
don't work your filters too much either, at this point they are probably not yet working at 100% efficiency yet and they need the dirty water so that your aerobic bacteria population can grow.
you shouldn't need to clean your filters at this stage, except perhaps if they are starting to clog up, and then do say, one tank per week, leaving time for the bacteria to replenish before doing the next.
discharging sediment from ,rearing tanks shouldn't cost you too much water: you shouldn't really have to worry about doing water changes at all.
just keep an eye on the ammonias, the nitrite levels and you should be safe.
also a good idea, especially with the smaller fish, to brush the walls and floor of the tank to remove the bacteria layer that builds up there. (three times per day or more with newly hatched larvae and early fry.)
keep posting, everybody is watching, if not posting.

right now your project is teaching many here something that most a few months ago would have thought impossible:

rearing what should end up as around half a ton of fish in a tank of only one cubic metre capacity! around 2000 fish per square metre of surface area, where i think thai recommended stocking density is five fish or so per square metre!

keep good records and work out where you can save a buck or two, soon you will need to produce your own fingerlings. (can do it in your bathtub!), and then you should be able to see a reasonable profit.

[highlander]

mellow or tsicar, just a couple of questions, do you have to season the new concrete tanks before using them also where can the water test kits be bought, is it best in uk or thailand ?.
and mellow please dont stop posting because as said lots of readers if not posters.

scotty

[tsicar]

mellow or tsicar, just a couple of questions, do you have to season the new concrete tanks before using them also where can the water test kits be bought, is it best in uk or thailand ?.
and mellow please dont stop posting because as said lots of readers if not posters.

scotty

new concrete will kill your fish, as the salts will leech out into the water.
if you want to stock fish within one day, paint a layer or two of diluted "flintcoat" (waterbased bitumen) on and let dry between coats.
otherwise, fill with water and empty after a couple of days, repeating about 3 times, then leave full of water for a while until the water turns green. test on a couple of fish and if they survive, you are ok.
thais throw in banana tree trunks and leave for a few days: seems to work, but i would still test a couple of fish before stocking properly.
water test kits from petshops.
bankok, or in your case, khorat- very good tropical fish shop there
all you need to test is nitrite, dissolved oxygen test for tilapia but not necessary for catfish at all.

[highlander]

mellow or tsicar, just a couple of questions, do you have to season the new concrete tanks before using them also where can the water test kits be bought, is it best in uk or thailand ?.
and mellow please dont stop posting because as said lots of readers if not posters.

scotty

new concrete will kill your fish, as the salts will leech out into the water.
if you want to stock fish within one day, paint a layer or two of diluted "flintcoat" (waterbased bitumen) on and let dry between coats.
otherwise, fill with water and empty after a couple of days, repeating about 3 times, then leave full of water for a while until the water turns green. test on a couple of fish and if they survive, you are ok.
thais throw in banana tree trunks and leave for a few days: seems to work, but i would still test a couple of fish before stocking properly.
water test kits from petshops.
bankok, or in your case, khorat- very good tropical fish shop there
all you need to test is nitrite, dissolved oxygen test for tilapia but not necessary for catfish at all.

thanks tsicar thought the concrete would need seasoning, and thanks for the pet shop advice.

scotty

[mellow]

We may be lazy typists but we like to read.

agreed.
i have been too busy sorting out my ant problem today, but have meant to post on this thread for a while now.
mellow, don't bother to size grade now. this should be done at an earlier stage. rather carry on as you were, then throw out or sell the non performers at the stage where about two thirds of your fish are sale-ready. the thais will buy fish as small as 100g and even smaller; just don't make the mistake of trying to feed them for another growth cycle.
at this point, stressing them with excessive handling could get them weakened to the point where they can pick up diseases.
as they are feeding well, handling can put them off the feed for a while, too.
don't work your filters too much either, at this point they are probably not yet working at 100% efficiency yet and they need the dirty water so that your aerobic bacteria population can grow.
you shouldn't need to clean your filters at this stage, except perhaps if they are starting to clog up, and then do say, one tank per week, leaving time for the bacteria to replenish before doing the next.
discharging sediment from ,rearing tanks shouldn't cost you too much water: you shouldn't really have to worry about doing water changes at all.
just keep an eye on the ammonias, the nitrite levels and you should be safe.
also a good idea, especially with the smaller fish, to brush the walls and floor of the tank to remove the bacteria layer that builds up there. (three times per day or more with newly hatched larvae and early fry.)
keep posting, everybody is watching, if not posting.

right now your project is teaching many here something that most a few months ago would have thought impossible:

rearing what should end up as around half a ton of fish in a tank of only one cubic metre capacity! around 2000 fish per square metre of surface area, where i think thai recommended stocking density is five fish or so per square metre!

keep good records and work out where you can save a buck or two, soon you will need to produce your own fingerlings. (can do it in your bathtub!), and then you should be able to see a reasonable profit.

The filters is where the water changes occur. Draining the settling tank, and other mechanical filters, rinsing and re-filling. The Ammonia levels are fine, but the Nitrite, and Nitrate levels are maxed out. Changed out a lot of water yesterday trying to get them down, also drained out the bottom of each tank. Somehow the fish are healthy though, eating well, swimming around, with a few doing the soldier at attention thing. The PH has remained at 7.5 from the start. I imagine it will be a while before the bio filter starts working. Don't know yet how to deal with these high Nitrate and Nitrite levels yet though.

[mellow]

For those interested in water chemistry:

Pond Water Chemistry

[tsicar]

watch those nitrites mellow,
the fish won't put up with them for too long before starting to get sick

nitrates not that important-fairly harmless.

perhaps go a day or two without feeding and keep doing a water change per rearing tank per day until they come down.
i wouldn't change water in the filters at this stage.

[mellow]

^ OK will try that. Thanks. We cut feeding back 40% since yesterday.

[Norton]

any updates on your catfish rearing venture, mellow?

Good inquiry. Keep the posts coming guys.

[Deris]

Do happen to have any pictures of you operation? It would be kinda cool to see.

[mellow]

Do happen to have any pictures of you operation? It would be kinda cool to see.

https://teakdoor.com/farming-and-gard...m-project.html (Our Little Fish Farm Project.)

[Deris]

Ah, you know I had looked at that post some time ago. Just didn't connect 1+1 to make 2.

[mellow]

^ Should have kept it all on one post.
Will update in original post.

[BillyBobThai]

tsicar, I agree that ant problems can be a bitch. I wish the powers that be here on TD, would deal with the ANT problem here.

Could not mellow have gotten his bio filter up and running by adding ammonia to the water for a period of time before adding his fish?

I would like to see you write a piece on how to raise catfish fry. How can I tell the sex of adult catfish?