Backyard Aquaponics
A place to discuss aquaponics

Does anyone know if swimming pools liners are toxic to catfish? The reason I'm asking is because my pool was damaged in storm and for safety reasons it shouldn't be used for fear of it busting. but if diameter is made smaller like 10' or 12' and 3/4 buried it would make a nice free tank in a hoop style green house. The reason I ask if it is toxic is because I released 100 of them in the pool last fall and all perished within 2 months while half the blue gill survived. But I'm not sure if the water turned after a cold front causing an oxygen problem or leftover chemicals from the pool. I may set up a test tank out of an aquarium lined with excess pool liner. I really like TCLinx's system and I am trying to save a little to get it going but I do not want any major flaws built that deep into the system. My other question is for TCLinx, my bluegill seemed to have been stunted in the Barrel ponics system, they actually did all their growing in the pool in the winter. Does it seem the tank is stunting the catfish, I remember when you lost one but it seemed to be a big fish. Whats your opinion?

I don't know much about bluegill but a barrel is not a big habitat for many active fish. Blue gill are not known to be really fast growers though.

There is another member somewhere with a system using a cheap pool as fish tank. I'm not sure how he is doing now but was having some major health issues with his channel cats. I don't know if the true cause has ever been found.

Catfish can be a bit more sensative to some illnesses/parasites etc since they are tender skinned fish. They are also not especially salt tolerant so dosing a system with a strong level of salt seems to stress them too. I don't intend to ever salt the catfish beyond 3 ppt again. As to why you lost all the catfish while the bluegill survived, hard to tell since there were probably so many other variables other than the pond liner. The catfish seem to like a fairly large flow of water. They will go off their feed in my system if I don't keep enough water flowing through their tank. They need a fair bit of O2 also.

I've also heard that bluegill can be really aggressive in tank culture. I know in pond culture bluegill and bass are usually stocked together for farm ponds and the bass will prey on the bluegill. In tank culture I've heard that the bluegill will kill the bass and you can't stock them together in tanks. I wonder if the bluegill were hard on your catfish in the pool?

As to size and stunting. Well, the smaller waterfall tank which has most of the catfish in it might not be growing them as large or fast as possible but they are definitely reaching eating size in that tank. I do have 5 of the catfish loose in the big tank (outside of the tilapia cages) to keep that tank cleaned up. I don't see those fish as often but there is one that is getting huge (though he was probably already eating size when he went into that tank.)

Should you use the liner for a tank, I'm not sure. Lining a small aquarium with the liner and putting anything but very small fingerlings in it may not be a good test. Large fish in very small tank are often stressed and any illness could be due to stress and have nothing to do with the liner. I don't know if that test would help you much. Now if you could to that test on a slightly larger scale (if you have any other way to support the liner at an appropriate size for the fish you have) with the chunk of liner, perhaps you could see how the fish you have left do with it. The liner is probably fine for the fish, better question might be what chemicals might leach long term and build up in the foods and then in you and family and not even be noticed for another 30 years when we discover it is bad for us. Who knows.

Hi jdphish and everyone.
Thanks for your informative posts.

Do you know if the catfish will eat live bait, such as the marbled crayfish ?
I'm at South Carolina, would the catfish survive winter over night lows of 15-20 degrees without greenhouse or cover?

Thanks,
Love this forum...

Most US species of catfish will eat live bait. Including crayfish. As long as the water didn't freeze solid the catfish will be fine. Like Charlie Little mentioned, long ago, they can survive under an ice covered pond. Had it happen a few times myself. Catfish are considered a warmwater species. They will grow best at temps above 65 or higher. Tilapia are considered a tropical fish. Most strains of Tilapia die when temps drop below 50. Sorry, my worldwide friends, all temps mentioned are F.

If you make a point of buying catfish that are raised locally, you can be pretty certain they will be better adapted to your climate than ones that come from further away.

When the water gets cool they will eat less but that is pretty normal for many types of fish.

Is catfish the only tilapia replacement that is not as sensitive to temperatures as the tilapia?
Does anyone know? Wouldn't want to depend on one species and find out that don't like it.

bluegill are pretty hardy... but are a little slower growing....


jT

Most of the alternatives are a little slower growing and some of them are a little trickier to feed. Bass, perch, bluegill, sunfish are all types of fish that one might see in US lakes which could probably be grown in tank culture.

Now if you are worried about liking catfish, you can go to the grocery store and get some US farm raised catfish fillets and try a few recipes to see what you think. Catfish is pretty mild fish, somewhat oily but without a strong fishy flavor in my experience (granted the only stuff I've eaten is what we grew and it is prepared or frozen very quickly after catching the fish.)

The flesh of catfish can be very dense which is the only complaint I've heard people mention that might still apply to Aquaponic catfish.

So I'm thinking about channel catfish for a pond project I'm looking at and one of my main considerations is something that can be self-perpetuating with not too crazy amount of work. With a good sized pond (10' x 5' x 3.5' deep, 1200 gallons) and with whatever goodies on the bottom that help (tubes, buckets, whatever) will they take care of replicating all on their own or does it take a lot of active involvement?

I think I remember reading that catfish don't lay eggs until they're three years old? So for the first couple of years I'd need to buy new babies to replenish the supply? Do big catfish eat baby catfish if I raised them together? Is there a specific time of year when they tend to lay eggs or dependent on water temp or light?

What is medium density for channel catfish for a pond like that? I probably won't have enough grow beds to run the pond at full capacity (at least not in the beginning), but I'd like to produce a good chunk of fish if possible.

So do channel catfish have a point in their growth curve with ideal size for amount of food eaten? Do they slow down a lot as they get older and bigger (1.5 lb. or bigger) such that it's not worth keeping them around that long or is the 2 lbs food for 1 pound catfish pretty consistent even as they get big?

Last question, anyone know of any good suppliers in Northern California?

Great thread, thanks for all the info

I was poking around the web and found two interesting links. University of Georgia has done some good info gathering on raising catfish, here's a link to a booklet they put together:

[url]http://warnell.forestry.uga.edu/service/library/index.php3?docID=46&docHistory[]=1[/url]

And for any folks in Northern California (besides me :-), here's a link to a place that sells channel catfish fry:

http://www.stillwateraqua.com/

If anyone knows of other good info, I'd love to see it, or if they know of any similar info about raising trout. I'm trying to decide between the two, but having a harder time finding info on small scale trout raising.

I don't know how easy it would be to get catfish to breed in a tank only 10 by 5. I have had four and now only three 4-6 lb catfish in my 9' by 3.5' tank with a container for "breeding" and they haven't done it. I expect those catfish are actually 3 years old. However, if you have a fish farm that sells catfish fingerlings near by, It is probably cheap and easy enough to buy new ones regularly.

Yeah, I think you're right, breeding catfish might be a ways down the road, especially if this fish farm turns out to be a good source. A trip once every six months or so up there would not be a big deal.

Now that I've switched in my brain from Tilapia to catfish, all of the sudden a few more spots in my yard are possible locations for ponds of various sizes. So what's about the smallest pond that works well for channel catfish? Is there a minimum depth? Is there a target ratio for surface area to volume?

I went to visit hydrophilia, and he got me thinking about bailing on the sump pump idea and just having a bigger tank that you don't stock that heavily. So what's a good medium fill rate for catfish in a 12' x 2.5' wide x 3' deep tank (600+ gallons)? He did another trick that seemed useful, he used the tank as his platform for his grow boxes. I get that when I need to do some work on the tank, I'll have to do some moving, but aside from hassles of moving boxes to access different parts of the tank, does covering the tank seem like an ok idea? Catfish like shade (I seem to remember) but does that mess up surface area oxygenation too much (assume I'll have some access for air to flow in and around)? Do you have your tank covered or open to light? It makes draining the beds easy and it seems like it would let me have the pump run a bit too long, overflow the grow beds (with drain holes 1" below the surface level of the grow medium so they don't really overflow) to do some extra aeration and water cycling.

One drawback of the spot I'm thinking of is that I wouldn't have access to a lot of grow bed space (without some complicated pumping). 250 gallons worth at 1' depth, 325 at 1.5' depth. I'm sure that limits the stocking rate a bunch. I've got a nice pump that should do 30 gpm up a few feet that I was thinking to leave on 5-7 minutes/hour, 24/7. Build in some overflow protection into the beds so that water drains out at 1" below the grow medium surface, and I can 6-8 complete water changes/day.

Ok, this is getting too far into potential design and before I get too into that, I'd love to hear from anyone with channel catfish experience any thoughts on the ton of questions I threw out. Thanks for any ideas.

It is already too cold this winter.

My quarantine system is completely out in the open, no roof, no greenhouse.

The plants are liking it but I'm fearing for the extra tiny catfish fingerlings. I don't know how well small catfish fingerlings can deal with the cold. I know adult silvers and blue gill can handle cold but when small they tend not to survive as well through extreme cold. I don't know if catfish compare in that way.

When I tried to put my hands/arms in today to pull up the pump and check it, it hurt. Now I'm having a little trouble typing because my hands are cold (even after washing dishes to warm them back up.)

However, even after all that, I only actually found 5 dead/dieing fish out of 140. I know there were at least two of those initial 140 that didn't look good to me when I put them in. Trick is, I can't see many fish in the tank, most of them must be hiding in the folds in the corners.

I think I'm gonna convert over to constantly flooded for the grow beds on this system for a while because I think it will help stabilize the temperature more.

I would avoid making parts of tank hard to access. Not being able to see into the tank easily is a real issue and moving grow beds out of the way to check on fish is not really a viable option. Keep in mind that a un-noticed dead fish in a system can cause huge problems and do you really want to move your grow beds when ever you want to catch and eat a fish? I have covers over my tanks to help block light and leaves but they are easy to open up like a lid on a box. My covers still let air in. It is not overly difficult to run plumbing just remember to size it plenty big enough. I have kicked myself any time I made something difficult to access.


One channel catfish for every 5-15 gallons of grow bed seems about right. Or 1lb of grown out weight per 5 gallons of gravel.

18 to 50 catfish per 300-gallon Rubbermaid Growbed. (I likely won't fill 'em to the tip top)
I am liking these odds.
We now have my son ordering whole Catfish at the local Mambo Seafood, that's 3 out of 4 lovin' it and the other one still gets fried fish (so fillets are an option for her).
I think it's Channel Cats for us this year. Staged in batches of 20-25 fingerlings at a time while it's warm enough. Wait, was the cannibalism question addressed?

Rick