Making your own Fish Food
Posted: Thu Jan 23, 2020 5:43 pm
During every training someone asks “what about making your own fish food?”. One of our students grows duckweed and black soldier fly larvae, dries them, and then grinds them in a home coffee grinder to make a floating fish food that her fish love. We estimate that if her labor is worth $10/hour, her fish food costs her about $12/pound when finished. This is because she only makes a small amount of food at a time. If she made a larger amount of food using slightly larger equipment, the amount of labor required to produce the food, per pound of finished food, would decrease. This is called “economy of scale”.
Making fish food on this scale is fine for a backyard aquaponicist with a hobby system, but if you are operating a commercial aquaponics farm it is impossible to support. In order to make your own fish food economically and sustainably, you have to do it on a scale that allows you to afford to “buy your own fish food”. If commercial food is $1/lb., your fish food needs to cost you LESS than that; or at least only slightly more than that, or it’s not sensible to pursue.
Black Soldier Fly Larvae
Good things about feeding your fish BSFL:
1. Cheap
2. Provides the ability to bio-degrade animal corpses and plant matter into fish food.
3. High in protein and fat.
Potential drawbacks to feeding your fish BSFL:
1. BSF larvae sink when put into the fish tank; this makes them less than the optimum food for fish like tilapia, which are hard-wired to eat floating food. Good for catfish, though.
2. The possibility of contamination of the BSFL with fecal coliforms, salmonella, shigella, and other potentially lethal bacteria through a number of avenues. I’ll explain a bit:
The real problem is that there’s so much at stake when you’re dealing with these pathogens; it’s not just a little stomach upset. If a few of your customers get a dose of the wrong e. coli from your vegetables, you’re talking about possible deaths, kidney failures, and other complications. I couldn’t live with the responsibility for this on my plate; how about you? Are you willing to risk it because you’re sure you’re right?
And for all you “compost is safe to use in aquaponics fans”, and “BSF is safe to use in aquaponics fans” your compost and your BSFL growing operating is safe, except for the rat that ran over it in the middle of the night and peed and pooped on it; and the flies that land on it in the daytime that were just laying their eggs on a dead animal carcass or bit of excrement a moment before; and the bird that lands on top of it and poops just before it flies away.
As a result of these things that happen in the real world, any contention that compost or BSFL is safe to use in aquaponics systems is simply not a scientifically supportable one. Unless you have your compost or BSFL growing unit in a sealed container that rats, birds, and flies CANNOT possibly visit, and you sterilize it before putting it in there, and sterilize any future inputs before adding them, then your compost and BSFL are exposed to all these sources of contamination.
And more: having had both interns and employees, I must add: “and except for the employee that disposes of the stable muck there, then covers it with grass to hide it, because it is less work than taking the stable muck all the way to its designated safe location”. Insisting your compost and BSFL are safe for your aquaponics is akin to insisting that Santa Claus really does exist.
So, you need to make your own decision on this; however as authorities that people look up to and take advice from, Susanne and I can never endorse something like this that MIGHT cause someone to die someday.
And as Dirty Harry once said: “Feeling lucky, punk?” (no personal inference here, just a cosmic comment on how people can manage to magically feel immune from consequences). Are you feeling lucky?
https://www.friendlyaquaponics.com/2015 ... fish-food/
Making fish food on this scale is fine for a backyard aquaponicist with a hobby system, but if you are operating a commercial aquaponics farm it is impossible to support. In order to make your own fish food economically and sustainably, you have to do it on a scale that allows you to afford to “buy your own fish food”. If commercial food is $1/lb., your fish food needs to cost you LESS than that; or at least only slightly more than that, or it’s not sensible to pursue.
Black Soldier Fly Larvae
Good things about feeding your fish BSFL:
1. Cheap
2. Provides the ability to bio-degrade animal corpses and plant matter into fish food.
3. High in protein and fat.
Potential drawbacks to feeding your fish BSFL:
1. BSF larvae sink when put into the fish tank; this makes them less than the optimum food for fish like tilapia, which are hard-wired to eat floating food. Good for catfish, though.
2. The possibility of contamination of the BSFL with fecal coliforms, salmonella, shigella, and other potentially lethal bacteria through a number of avenues. I’ll explain a bit:
The real problem is that there’s so much at stake when you’re dealing with these pathogens; it’s not just a little stomach upset. If a few of your customers get a dose of the wrong e. coli from your vegetables, you’re talking about possible deaths, kidney failures, and other complications. I couldn’t live with the responsibility for this on my plate; how about you? Are you willing to risk it because you’re sure you’re right?
And for all you “compost is safe to use in aquaponics fans”, and “BSF is safe to use in aquaponics fans” your compost and your BSFL growing operating is safe, except for the rat that ran over it in the middle of the night and peed and pooped on it; and the flies that land on it in the daytime that were just laying their eggs on a dead animal carcass or bit of excrement a moment before; and the bird that lands on top of it and poops just before it flies away.
As a result of these things that happen in the real world, any contention that compost or BSFL is safe to use in aquaponics systems is simply not a scientifically supportable one. Unless you have your compost or BSFL growing unit in a sealed container that rats, birds, and flies CANNOT possibly visit, and you sterilize it before putting it in there, and sterilize any future inputs before adding them, then your compost and BSFL are exposed to all these sources of contamination.
And more: having had both interns and employees, I must add: “and except for the employee that disposes of the stable muck there, then covers it with grass to hide it, because it is less work than taking the stable muck all the way to its designated safe location”. Insisting your compost and BSFL are safe for your aquaponics is akin to insisting that Santa Claus really does exist.
So, you need to make your own decision on this; however as authorities that people look up to and take advice from, Susanne and I can never endorse something like this that MIGHT cause someone to die someday.
And as Dirty Harry once said: “Feeling lucky, punk?” (no personal inference here, just a cosmic comment on how people can manage to magically feel immune from consequences). Are you feeling lucky?
https://www.friendlyaquaponics.com/2015 ... fish-food/