Forgive me if there is already a post in the forum on this one, I couldn't find one. I am going to be building an aquaponics system in a couple of months here once I move to my new place. I am in Mexico.
I would like to do a little shore fishing down here and it got me thinking about what I should do with the fish guts. Fertilizer came to mind, but then also I remembered that someone once told me that you can take your excess fish from your aquaponics system and and feed them to your existing fish as food.
Since fish guts can be such a good fertilizer I am thinking it could help the whole system (if it doesn't ruin the water quality for the fish)...
Can anyone shed some light on the possibility of doing this, any implications for the system, and the best way to turn fish guts into food (blend and dry it?).
I fished yesterday and after filleting fish buried the remains in my compost bin to feed black soldier fly larvae and redworms. The larvae and worms are fed to the fish.
I supplement my catfish's pellet diet with fresh anchovies that I get on fishing trips (leftover live bait). It really seems to crank up their growth rate. I think that if you just have innards, there will be extra goo and little bits that the fish can't eat, and you run the risk of clouding the water and elevating bacterial load, which can compromise DO.
Personally, I would think about using a black soldier fly culture to convert your fish scraps into a protein and fat-rich fish food supplement. This would be a lot easier than blending and drying.
Composting to remove all moisture from the fish meal would work. This would remove all of the pathogens and once dried it can me ground and fed to the fish. Although it won't have the high standards of processed aquaculture fish pellet. The manufactured pellet has the heavy metal removed. As long as you are fairly sure there is little in the way of pollution affecting your wild caught fish it should be OK. You can build a simple solar bin to speed up the composting process if sunlight is not an issue where you live. With solar composting you can have the final product in a matter of day/days. If you really want to go further you can mix the meal with a simple basic basal diet(recipes available on the net), pass it through a hand mill and...........instant fish pellet!
Sorry, but I'm going to disagree with the moderator on this one. Composting is not a good idea.
Kai has fresh fish bits--a great source of protein--so it doesn't really make sense to let this good stuff rot and turn into slimy mineralized compost as a step towards feeding stock. That would be good for the plants but not for the fish.
The problem with throwing a bunch of goopy guts and skeletons into your fish tank is not pathogens so much as the cloudy, bacteria-laden water you'll have after a day, thanks to the nutrient-laden goop fish aren't able to eat.
Feeding scraps to stock is okay if you're selective and provide your fishies with rinsed chunks of edible material that will be entirely consumed. For the rest, feed it to the BSF and then collect the pupae to give to your fish.
I wonder if you could simply dry it with an electric food dehydrator or in the oven. I'd imagine it'd be rather smelly though...
Thanks for all the responses guys (and quick)!
The more common type of fish down here (that I would catch) are "Bone Fish." They are pretty good eating.
I definitely don't want to screw up the balance of the system and add anything that would consume the DO.
I hadn't thought of using the fish to growing blackflies. I was experimenting with juicing scraps and was able to get blackfly larvae to grow pretty quickly down here, so fish could help.
My wife and I make juice fairly often. On that note, would juicing pulp make a decent fish feed (if dried)? If I have fish guts feeding the blackfly system then I would need less juicing pulp for that. It usually is composed of apples, carrots, cucumber, celery, lettuce, ginger, beets, and or lime.
Great discussion guys!
I think if you poke around the mangroves, you can find some robalo, too (very tasty and fun to catch!) I have never eaten bonefish. The only place I fished for them was the Bahamas, where the guides will tell you they're no good to eat, but any local you ask will tell you they are delicious (baked, with bird chiles).