Backyard Aquaponics
A place to discuss aquaponics

I have a few questions about feed.

I have seen protein % for feed for different types of fish. Here is my guesses about the reasons for this.

The % seems to be give optimal growth for best price.

I just want to double check my info here.
If I were to feed a higher % what are the drawbacks? As in will it hurt the fish if I were to say feed tilapia 40% feed beyond the juvenile stage?
(this is assuming that the system can handle the extra waste load and the water quality will remain good.) Is the only drawback of using the higher protein feed just the added cost?

Reasons for asking are because the food comes in 50lb bags and I'm searching for an appropriate for for both channel catfish and blue tilapia in tank culture. It seems to be that most of the inexpensive food is meant for fish in say a farm pond. Perhaps this feed would be good enough for the larger tilapia but I'm thinking that the catfish and younger tilapia need a more complete and high protein food for good growth. The intensive culture food is really $$ though so I'm wondering how important it is to buy good feed for these two species of fish.

Any opinions there?

I can get pond diet which is a fish food with a protein % somewhere in the 30s. It comes in 20lb bags and the pellets are appropriate size for the tilapia. It is a food meant for feeding fish in farm ponds so is probably not that complete.
The feed store accross the way sells catfish feed that again is probably meant for farm ponds. The protein % is in the 30s again but the pellet size is a bit big for the tilapia though the little guys will try to eat anything.
I've gotten some of the 40% intensive culture feed with the good size pellets (small enough for the tilapia) and both types of fish really like it but it is twice the price of the cheap stuff I can get.

Generally higher protein requirement as youngies. Some diets will have 50% protein in say dust form. Lower protein diet is suitable for a non commercial growout, no worries. That 30% stuff sounds fine for both soecies.
Each species does have specific requirements that are unique to itself though. A lobster needs different stuff to a sand worm bc the sand worm has no dietary need to produce a shell to live in.
If the food profiles for the two are similar, you should have no drama.
Throw in the odd bit of live feed to flesh out the diet and things should be ok.
Look at how they grow in nateure.
In Australia, silver perch are essentially bottom feeders and do not have a high protein dietary requirement. Trout however grow very quickly and need that extra protein for that growth.
Hope this helps.

I do expect that if I breed the tilapia and grow some fry, I'll be using the 50% high protein starter food that I can get in meal form. I suppose I'll see how the fish do on the different feeds.

TC,,,Tilapia on grow-out will do fine on 30%,,,similiarly the cat-fish,..........
once you get them at 4 inch -5 inch,,,cheaper food makes sense ( the 30% protein is fine),,
smaller pellets are preferred forTilapia,,,maybe a mix of floating and sinking ,,to make sure the cats get a fair share.

Few links FYI TCL....

http://books.nap.edu/openbook.php?isbn= ... 15&page=R1

In Section 7 of the above link there's a table (7) showing nutritional needs for some common fish ... http://books.nap.edu/openbook.php?recor ... 15&page=62




And another good background article

http://www.ext.vt.edu/pubs/fisheries/42 ... 0-256.html

I trainned retrievers for over twenty years, and have been involved with large livestock as well. Over the years I have learned that very few people including vets understand the make up of feeds. I found that the best way to learn about feeds is to speak to the nutritionsist on staff at the company who produces the type of feed you are using. One of the key things I learned is that a feed mill can produce a feed made out of shoe leather and it can have a 50% protein level they can easily manipulate this #. I know from dealing with canine athletes that it is important to have a good protein to fat ratio and most feeds tend to be on the low end of the fat spectrum. I understand that you are not trainning your fish to retrieve but you still want a pretty high fat content especially during the colder months because fat is more of a sustained source of energy where as protein is burned in the body very quickly. It is also important to pay attention to the ingredients as well, you don't want a feed that has alot of filler, which will probably be listed as ash. Your protein will be a meat or meat meal and will be listed first or second on the ingredient list and then your fat source will be listed and will probably be some sort of grain. Animal feeds are just like people food and what ever is listed first is what the feed has the most of.

TC, I bought Barra pellets at the beginning of the season, but ended up with SP fingerlings

Barra pellets have a protein level of 44% minimum
Silver Perch..................................35%

Fish have eaten the barra pellets with relish and I have not seen any adverse side effects...mixed their diet with lettuce leaves etc to add a variety and reduce the protein level...so if you go for a higher protein then look at supplements to assist

Supplementing the tilapia with veggies etc is easy but the catfish don't seem interested in anything but bugs, pellets, and worms.

I was actually rather surprised that most references I've found for protein % in food for different fish recommend less protein for catfish than for tilapia? Is this just because most catfish are raised in earthen ponds and supplement their diet naturally?

Logically, the feed requirements for fish in recirculating tank culture should be a bit different.

(Just so ya all know, I'm not actually worrying this topic. It is more an academic out of curiosity kind of question because that is what these kind of forums are for, discussions. I have a few different feeds that I am testing out. Eventually I'm just going to use whatever feed is easy to hand, somewhat appropriate, and economical.)

another thing in this discussion.

We can only (easily, "cheaply") get barra pellets at about 45%. We have had them of all different sizes and float/sink capabilities. As our fish started out with floating pellets, that's what we all got used to. It is very easy to feed sufficient food with floating pellets in a black tank.

With sinking pellets you have no idea at all if the dark fish in the black tank are eating them. I've probably been under feeding a bit over the last feed bag to be sure it was all getting eaten.

Last week we got another bag (Marine - floating ) and it is very pleasing/ relieving/ fun to watch the fish striking at the surface again.

I had to get in the tank the other day to readjust the air pipe and I had a feel around the bottom of the tank to make sure there wasn't a pile of rotting pellets down there. And there wasn't *phew*

The perch get supplemental feeds of any bugs/ worms/ caterpillars, spinach leaves, azolla and duckweed.

Hands up those who want to see a picture of Jaymie in the big tank

too right.

talking of different feeds, I have a heap of rabbit feed left over from the two I had a couple of months ago (and no I didn't eat them), I have noticed they are made up of a fair amount of lupins.
I have lost the packaging so don't know what else they consist of but would imagine there would be some sort of fodder/grassy stuff (very technical).

Now the real question is do I feed them to the trout, could I possibly use them in a 50/50 ratio with the skretting I have?

Any opinions

I would certainly try it as a fish feed...probably doesn't float so would be difficult to gauge if all eaten but could be used as part of the feed every 2-3 day intervals to get rid of it...or find another rabbit fanatic to take it off your hands

Do you have a dirt garden gnash? If so, then most animal feeds make really good fertilizers. I often use alfalfa pellets in the garden.

You could try tossing a few pellets in to your fish and see what they do with them? I don't know if anything in them would be bad for the fish. I always though trout were carnivores so I don't know if rabbit food would be very appropriate but who knows?

trout feed so fast they wouldnt know the difference

Just mix it in with the high protein.