Backyard Aquaponics
A place to discuss aquaponics

Hello,
Loooooooooooong time luker first time poster.

I have struggled to find anything somewhat scientific in terms of an analysis on fish fed an "artificial" diet vs natural, wild caught fish of the same species.

The reason I ask this is I am a firm believer in grass fed beef vs grain fed feedlot. Sure the animals grow and "meat" is created, but there is no question between various metrics such as fatty acid profiles, etc of an animal fed a diet they are meant to vs one that optimally puts on weight in a caged environment.

Before I take the plunge into aquaponics or aquaculture, I want to know the same for fish. Has there been any similar sort of studies? Are aquaponic trout even close to a wild caught trout for example and perhaps more specifically what sort of feed gets them closest?

I am blessed to be renting on a farm with a few dams, I put 100 silver perch fingerlings into one of them (not feeding them only whats naturally available) 10 months ago, I have bass in the river on my boundary and am 10 mins to the coast so in terms of wild fish I have options, but I am also interested in the business side of things, particularly looking into yabbies right now but curious as to aquaculture of fish. I would never feed a cow grain and wonder if its the same thing for fish.

It "works" but is it even comparable?

Thanks
Dan

I run my system off of bass, and only feed them wild caught food. Most of their diet is minnows, crawfish, and bugs.

Thanks, I definitely want to do that for myself, is it a health choice for you? or monetary? (presuming wild caught food is generally free?)

Well it started because I could not get my tilapia to make it through a winter. The bass are very hardy, have not lost one in well over a year (except the ones that jumped out). I have a fairly large pond behind my house, so I just put some minnow traps out and feed them what ever gets in them. Lots of baby perch, and minnow mostly. Oh I almost forgot I have 2 red eared perch in my system also. I am doing it mainly because I believe it is healthier, it is way easier for me just to go and get catfish and feed them commercial pellets.

The comparison is not exactly apples and apples.

Cows are fed a diet in feed lots to fatten them and while a good deal of science has been done on how to formulate feed lot diets it is a ridiculously small body of knowledge compared to the study done on aquaculture feeds.

I take your point about grass fed versus grain fed beef and I definitely prefer the former. With AP at any sort of scale you need to feed a commercial feed. At small scale you can feed more natural foods but it is a fair bit of work.

Thanks, I agree about the work, or no work in healthy dams and have to wait twice as long with probably a fraction of the carrying capacity. At the same time I think there is a market for this naturally raised fish just like grass fed beef is making a come back and is now more expensive then the grain fed stuff.

Perhaps a better analogy is instead of feeding grain in feedlots, you feed them hay/lucerne which would be as natural as you can get in that environment, especially if fed a variety of different hay.

Are there any food providers out there that do any tests and make them public? Rainbow trout or Silver Perch are probably the two most likely fish i will have success with, and yabbies.

Not to my knowledge on trout but I'm sure there is on salmon.

The problem with natural foods for AP is that most AP species are carnivorous. If we all shifted to herbivorous fish then that would be another matter. Ages ago people have talked about lights to attract insects and such but depending on your location that could be very environmentally damaging.

I heard on the grapevine (cant remember from who) that Challenger TAFE in Freo had done a study comparing the growth of Barra fed on pellets and Gambusia (Mosquito Fish). Apparently the growth rate of the fish fed on the Gambusia was far greater than those fed on pellets.

That's interesting.

This is a decision every person ultimately has to make for themselves. but yes, there is a lot of information and research out there about farmed fish nutrition that you can use to decide what is right for you. Fish farming is a very big industry. Choose the fish you are looking to raise and search the Internets, specifically agricultural centric universities for nutritional data.


High quality fish foods are usually nutritionally balanced for a specific species and mimic exactly what the fish species needs to grow optimally.

keep in mind the typical live feed conversion ratio is about 10 lbs of live food for 1 lb of fish growth. where fish on commercial feed is closer to 1.7 lbs of food for 1 lb of fish growth.

The thing about growing optimally is that you might end up with fish that are not healthy. Optimally is defined differently for different people.

Take the cattle feedlot example, optimal is weight on at a certain speed and the end product is "meat" but when you look into it, its hormone filled, the omega 6 ratio is unhealthy and the animal not healthy.

Optimally for me would be no different to a wild caught fish and im not sure i can get that from a commercial feed, though it is entirely possible and im not ruling it out, i just have not seen a food manufacturer put up any lab tests and use my definition of optimal as a metric, its all about growth rates.

well my definition of optimally is not necessarily fastest growing. And generally speaking, a healthy, happy fish is going to grow fastest.

like i already said, high quality fish foods are designs specifically for a species needs.

It's seems true that high protein feeds can help fish grow faster but apparently over long term can cause liver failure and death in the fish. My fish dont live long enough to start having liver problems so it's not a concern for me.

Hormones in fish food is illegal in the US and from everything i have read it wouldnt help them grow faster. We arent talking about cattle so you should really stop trying to debate things you know nothing about and research it. The info is out there.

Hormones are not used in Australia either (well not legally) which is why the coles or woolies add is border line deceptive.

It is easier to feed cows a balanced diet by giving a mix of grain and fodder with whatever supplements. Getting it right for fish is much harder so much more work has gone into solving the problem.

Apologies for upsetting you, my analogy is not about fish, but its a quite well documented example of a farming industry putting out a product that later turned out to not it was cut out to be. Considering im trying to have a similar discussion along those lines I felt it pertinent.

If its out there can you link me to even 1? Something comparing other metrics other than growth rates. I don't like the idea of eating fish before they potentially develop liver problems and calling that not concerning.

I have found no reading on any species in Australia, I even went old school to the library and have 6 books on Aquaculture in Australia. Have not expanded my search worldwide. To me, if a commercial food manufacturer put a farmed fish raised on their feed alongside a wild caught one and showed full lab tests on each, and it was close or identical, that company would be without competitors.

I don't know where you get your info from but here is an article from the M.L.A ( meat and livestock ass. ) they might know something. Naturally ocurring hormones yes but added none the less. I don't think 40% of cattle produced in Australia would be on the black market....Sorry Stuart but I think your statement is deceptive on a couple of points.
http://www.mla.com.au/Cattle-sheep-and- ... promotants
I understand never used in lamb and phased out of chicken in the '60s