Fish Density

[Don McCammon]

My primary interest is in raising fish.  The vegetables are nice but I want to grow as many catfish as quickly as I can.  I have a net 500 gallon tank.  Can I stock it with as many as 200 catfish if I aerate the water?

[TCLynx]

How big do you intend to grow them?  200 small fish provided you have ample filtration, flow and aeration are no problem in a 500 gallon tank.  However as they grow you will have trouble keeping enough dissolved oxygen in the water even with supplemental aeration.  You would probably need to use oxygen if you plan to grow them to much more than 1 lb each.

 

Now if you are a very experienced fish keeper you might manage well enough up to a point but if you were an experienced fish keeper, you probably wouldn't need to be asking this question.

 

I have grown over 100 fish out fairly large in a 700 gallon tank with about 1400 gallons of media beds.  I use supplemental aeration.  Currently though, I only have about 23 channel catfish in that tank and many of them are really big.

[George]

What a nice fish fry you could have.

TCLynx said:

  Currently though, I only have about 23 channel catfish in that tank and many of them are really big.

[TCLynx]

Well some time I'll have to harvest the rest of the big guys so I can move 70 of the newer fingerlings to the 700 gallon tank for grow out.  I've decided that 70 channel catfish for a 700 gallon tank in my big system is a fair number for grow out.  10 gallons per fish allows them to grow big fairly fast and we like em big!!!!!  Much nicer to clean one fish instead of 5.

[George]

Fish density is a question I've been wrestling too and I'm leaning more toward conservative lately.  The main game for us will be plants.  Conservative for me will be a pound of fish grow out per  five gals of water with 1 1/2 to 1 ratio of filter media to water.  If ammonia begins to rise we'll just start harvesting fish at that point or there are other ways to deal with it such as add grow beds or do water changes or possibly some combination.  I expect it will be at least a year from stocking before that density would possibly begin to be a concern but we shall see.

[TCLynx]

Once a system is mature, one can sometimes get away with fairly high density without issues of ammonia build up.  More likely you will find that you need excess filtration capacity to deal with solids and nitrate removal but that will all depend on system design.  If stocking to extreme density, the most likely limiting factor here in Central Florida with channel catfish will probably be dissolved oxygen come warm weather.  Also, the more extreme the stocking, the more extreme the situation if there is a disease outbreak.  Be very careful of overfeeding as the weather starts warming up.

[Don McCammon]

I raise trout in West Virginia in my trout pond and get two inches of growth per month.  I really don't know what to expect in Florida with catfish.

[TCLynx]

I can usually get channel catfish fingerlings to grow up to the 3-5 lb range in aprox 12 months

[George]

My other half is prejudiced against catfish but we'll definitely try some to see how she likes them aquaponically raised.

TCLynx said:

I can usually get channel catfish fingerlings to grow up to the 3-5 lb range in aprox 12 months

[TCLynx]

Grown aquaponically, there is very little difference between them an tilapia as far as flavor goes.  Catfish can also yield bigger fillets than a tilapia.

[David Hart]

George when cats are raised on commercial feed, they have more of a mild taste then wild. Purge them for a few days, even more so.

 If she only likes something really mild, like 'whiting'...they will still be 'a little' stonger then that.

Hope she likes them....

[TCLynx]

as far as I was concerned, catfish and tilapia taste pretty much the same.  Very little flavor so they take on what ever flavors you cook them with.  We also never bother purging our fish anymore.  I think moving them to a small tank for purging actually caused more stress and didn't improve flavor as far as I could tell.

 

I think the best thing is to net, kill and clean all as quick as possible so everything stays really fresh.  John puts the cleaned fish into salted ice water after cleaning before cooking.

[David Hart]

TC, has John ever tried soaking them in milk ? I've hreard of it...never tried it myself.