Catfish in raft beds?

[Averan]

Anyone have any good reasons why I shouldn't raise catfish in DWC raft beds?

[TCLynx]

1- it makes it nearly impossible to inspect or check on your fish and make sure there are not dead ones in the tank.

2-Nearly impossible to feed the fish without fouling the rafts with uneaten feed.

4-Most raft beds are too shallow to grow large fish well.

 

[Averan]

Well, it looks like I'll be alone on this, experimenting with something new!

1. ok, a little tricky.  i can see how a dead fish could get hung up in the roots under a raft and not just float down to the outflow end of the bed where i could easily spot it and fish it out.

2. i thought catfish were fed a sinking pellet?

3. err 4. i'm building my own raft beds and would add extra depth to accommodate fish.

I think that for my home system #1 is not a problem....for a large commercial operation it very well could be.  I've seen so many tank setups now where you can't even hardly net the fish let alone see them.

[TCLynx]

Plenty of systems put some mosquito fish in their raft tanks but go at your own risk putting fish you will actually feed into raft tanks.

 

I hate when I can't see the fish or tell if they are eating the feed and unless you are going way way low density, there is usually some form of filtration between the fish tank and the raft beds to keep the solids from mucking up the plant roots.

 

Need lots more aeration in you are going to be having big fish and feeding them in the raft beds.

 

And People have also occasionally run into problems with fish getting up on top of rafts that they have put in their fish tanks.

 

I've always fed my catfish floating pellets, too hard to make sure you are not over feeding if you use sinking pellets, especially if it is not easy to see the whole bottom of the fish tank at a glance.  Uneaten feed is a quick way to have an outbreak of a couple different common catfish diseases.

[Averan]

You don't actually have to feed mosquito fish.  They eat bugs, excess food and algae when left to their own devices.

The feed part seems like the hardest to address....I realize that sinking feed will quickly flow along the bed and out of the tank before it is eaten!

Fish poo won't be a problem as my design is high-flow pulling all solid debris down and out, which leads to the feeding problem.

Yes, I am aiming for a low density system, supplementing nutrients with composting worm bins.

Thanks for walking through this with me....I've really wanted to try out a space-saving design and like a lot of things about having fish in a long stream-like trough rather than a deep cubical tank like an IBC.

[Averan]

Just thought this through a little more....overfeeding won't be a problem.  Any uneaten food will flow right out and into a media bed full of worms which will consume the fish food just as readily as the poo!

My approach is to recreate nature.  In my mind a raft bed is a flowing stream, not a stagnant pond.  With proper flow all solids will be constantly flushed out, keeping the raft bed clean enough for the plants.  Also, if I can actually get this to work, it means that I can maintain lower stocking densities with fish spread out between raft beds.  Each fish would have access to a much greater volume of water than if they were kept in a single tank.

[TCLynx]

What kind of catfish and how big would the raft tanks be?  How deep and wide?  I've been growing channel catfish and they get quite big so I don't think they would be all that good a choice for this kind of culture, however something like bullheads might be more appropriate for this.

[Averan]

4' wide x 2' or 3' deep by 26' long.  Catfish, trout and koi are very well suited for living in shallow water. I've paddled on many FL creeks and rivers and the water was never very deep and always full of aquatic plants and loads of some very big fish!  With catfish and their habit of cruising along the bottom, I believe that a long flat tank would make them feel right at home.  At least more so than stuffing them in a 55gal barrel!  Your tank for the Channels is 700gal?  The raft bed I'm designing will be between 1500 (2'deep) and 2300 (3'deep) gallons!  I could stock at the same density as you have in your 700gal tank and still have between 800-1600 gallons left for the rafts.

Here's another way to think of my system:

It is primarily a media-based system where I use planted rafts as a lid for my fish tank.

If the fish are getting too big, I'll just eat them!  =)

What other important differences do the Bullheads have?  I'm considering alternating between trout and catfish between cold and hot seasons.

 

[TCLynx]

Bullheads are smaller than channel cats and perhaps a bit more forgiving.

 

I've decided a 2' deep tank is not deep enough to grow out catfish for me.  (And growing catfish in a 55 gallon barrel is completely ridiculous to me.)  I couldn't keep my catfish happy and healthy in the 300 gallon stock tank fish tank.  My bluegill seem to be doing better in there.

 

I think the minimum water depth I've managed to grow out catfish in was 25 inches of water.  So the tank needs to be deeper than 2' to provide enough water depth.  So somewhere between 30-36 inches of tank depth should provide enough depth for fish and rafts.

 

Definitely provide aeration in your raft beds if you are putting fish in them with the plants.

 

I'm not sure the season is really long enough to alternate between catfish and trout unless you are starting with really big fingerlings or eating them really small.

 

And while you might manage catfish under rafts, I think trout may be more problematic especially for feeding in such a situation.