Backyard Aquaponics
A place to discuss aquaponics

Thanks for that.
It seems the Wels catfish is the main one but at upto 2m long and 100kg+ you`d need a pretty big tank

Wels catfish are silurus glanis, they are growed out in east europe.
There is a farm that grows them in the east of France on a hot water well.
They grow fast and they say that they taste good, i think they'd be a good AP fish because they grow fast the first year of life, don't need to much tank size and are not to aggressive.
The only thing is to work in the dark, i've seen the workers work with headlamps like miners.
If you can get to fingerlings, i suppose it would be a good try.
I'll see if i can get a hatchery contact and get them on my hatchery list.

Catfish in nature need something to get under as a nest. They will burrow under a rock, tree stump or in beaver holes along the bank. The female can lay 1000 eggs for every pound of body weight. After the eggs are laid, the male will move in, fertilize the egg pile and guard the nest. Perhaps a separate breeding tank is needed with stuff for them to get in under and a gravel bottom as this is what they prefer to fan out an indention for their eggs.

This breeding time is when crazy folks get in the water and do the "Noodling"...they feel around under the rocks and in holes with their hands. The catfish guarding the nest will in defense, bite the intruder who grabs hold of their jaw and wrestles em out of the nest. They even have noodling tournaments with weigh-ins and the whole bit.

If bitten by a catfish, don't immediately pull your hand or fingers away quickly, wait for it to let go. The rough lip will extract your skin if you do but won't hurt at all just clamping down.

Okay here is my contribution
Mind you this is for channel cats only and is mainly for wild caught fish although the temps below were all done in labratory studies.

Temps
Lethal limits for channel cats 100F+
Stressful temps that can seriously harm fish 95F - 100F
Summer Norm in southern range 88F - mid 90F
Optimum growth range 80F - 88F in lab tests
Perfered temps 75F - 82F
Summer norm northern range 70F - 80F
Winter norm southern range 45F - 55F
Winter norm northern range 33F - 40F

Select stock from northern or southern stock dependent on your normal temps and how you will set up your system.
At temps of 72F and lower feeding begins to drop off and usually stops in the southern range at about 55F it can go considerably lower in the northern range but usually stops at 42F or lower.

Dissolved Oxygen requirements
1mg/l Lethal
2mg/l Cats gulp[ air at the surface
3mg/l or less fish are stressed, growth slows and fish are likely to contract disease.
+5mg/l needed to support successfully a large stock of fish
+7mg/l Optimum for growth and health

PH requirements
Low end PH too Acid -6.0
Normal range 6.5 - 8.5
High end PH too basic +9.5

Salinity requirement
normal 0 - 4 parts per thousand
tolerated with reduced growth rates +4 - 20 parts per thousand
lethal if continued contact to +20 parts per thousand

Prefered natural foods (Wild fish)
Small fish birth to 6" - microcrustaceans and very small crustaceans, rotifers, aquatic insect larvae, terrestrial insects.
larger fish +6" - crustaceans, larger aquatic and terrestrial insects rodents and reptiles, forage fish.
Extremely large fish usually feed on very large crustaceans and forage fish exclusively.


Sexing channel cats rule of thumb
Fish need to be a couple years old before this is noticeable
Males very dark blue to slate color, broader flattened heads with conspicuous bulging muscles behind eyes flowing towards the top of the head.
Females lighter colored smaller rounder less bulky heads and rounder more robust body section.

I have found they don't spawn reliably until 3 years old. Also, I generally figure 3000 eggs per pound. Never counted them but it works out when the fry are counted.

Badfish03 thanks for the info.

Great info guys, exactly what I had in mind when I started the thread!!!!

I need to have the cook take a picture of my inspecting the fish position. Probably very funny since the edge of the tank is less than a food above the walkway and to see the fish well, one often needs to close the cover over themselves. It sometimes means being splashed by the fish as one watches them eat.

An observation I have made is that they don't seem to have very good eyesight. I suppose it's good they have the whiskers. They seem much more disturbed by sound or huge light changes (like they all head for the bottom as the cover opens or closes.)

Any time I have seen flashing, there are other fish around. The bottom section of the tank is not so huge that a fish can really get off by itself when they are all milling about the bottom. As they are becoming more comfortable with their home they are spreading out a little more when the cover is closed.

I did notice a little chasing going on tonight while watching them. There are a couple fish that are pretty large (over 10") while the smallest ones are probably actually under 5". I have seen at least one of the really big ones go zomming off like it is chasing another fish. I don't know if that is really the case but none of em seem really beat up as far as I can tell.

It sounds to me like they`re just a bit frisky, they do seem to enjoy bodily contact by weaving around each other while they`re swimming.

Targetted aggression is hard to miss as they go in like an aquatic pitbull and are relentless ..a dog shaking a rag comes to mind
The victim will look like its fallen into a bees nest with red bite marks all over.

None of them look beat up like that.

There is still one medium size fish with a dorsal spike showing a white tip.

And now this morning, one of the smaller fish has a dorsal spike that looks almost entirely white (perhaps a little raw two) It wasn't that way yesterday evening during feeding. I'll be keeping an eye on that one.

The biggest fish I sometime see in the strawberry pot like he is guarding his lair.

I worked on a Catfish farm for a few months, mainly in the hatchery. Just thought I would mention what we did to breed the fish. As mentioned before, Catfish like holes, crevaces to breed in. So we put buckets, barrels etc about 2 ft long and about 1 ft diameter with a hole cut in one side anchored with bricks so they sit on the bottom of the pond. Then every few days someone sticks their hand in the barrel to see if there are eggs Dont know how this would work in a tank setup... but just wanted to share it in case it could help

I am noticing a bit more flashing going on and it does look like they are trying to rub themselves on the bottom most of the time when I'm seeing it.

I have plants in the system so probably would not want to go really extreme on the salt, would a dose that won't kill the plants still help the fish?

The tanks that the fish were taken from at the fish farm I believe were salted (the guy at the farm said they salt the catfish whenever they handle them so I took that to mean that the tanks were salted) I don't think the ponds were salted as that would probably not sit well with the EPA.

I was thinking about trying to net out the little one with the injured looking fin and giving that one a salt bath but it is several of the others doing the flashing and trying to catch them would probably be more stressfull and perhaps cause more harm than good.

Give a go at 3ppt for the fish without attacking the plants.

Could you catch one and check it out in an aquarium or other container (see through type), just to see if they have white spots or marks on the sides.
I have been told that they were sensitive to white spot disease because of there very small scales and thin skin. Small scales gives more joints between the scales and then more surface that could be a contact between inside and outside of the fish. Handling ususally takes the mucus off which is an antiseptic bareer for the fish. Apricot almond oil will be good for protecting the fish but it is really very very difficult to find out of the fish farming use (called LABRAFIL here).

Two things could be going on, or bacteria/fungi attack or parasites.
The two could be linked to the release in the fish tank, different waters, handling, transportation and all the stress induced by it.

The two can be solved with salt, permanent 3ppt will reduce bacteria growth. If white spot disease, 3 ppt will be good but maybe go for a flash salt bath of 10 ppt in a separate container for an hour.
There was a thread on white spot with lots of infos on it.

Thanks Amacatfish, I'll look for the white spot thread.

Any chance someone can help me figure out the calculations on how much salt will to get a ppt per gallon of water?

This has always been a challenge when some one says use some weight of something per some volume and I'm sitting there with measuring cups and spoons still wondering how much.

I've posted on the other thread but a tea spoon is 5 grams.
i've worked out salting to be a handfull for 20 gallons more or less, this is what i do but i don't know what it comes out to exactly and is not linked to an AP system.

TC, metric is so much easier to use to figure out ppt. Calculate your liters, then 1 gram of salt per liter is 1ppt. Salt packages are marked in grams, so even if you can't weigh in metric, you can get close using the package labelling.

Janet,
My system is more than 2300 liters. Kitchen salt packages might be marked in grams but I didn't want to spend that much on salt. I got a package that is marked in lbs or kilograms. I had to measure in pounds as that is all the bathroom scale would do.

All sorted out in the salt thread in the info section now anyway.