Backyard Aquaponics
A place to discuss aquaponics

In my aquaponics system, the main fish being raised are Channel Catfish, and in a separate tank I am also attempting to raise Guppies as a primary food source for the catfish.

Catfish, being omnivorous and greedy, will eat almost anything. Right now, they're small (5"-7") and can't fit a guppy in their mouth. I am feeding them on commercial fish pellets but eventually would like to feed them the guppies, grubs such as soldier fly larvae, as well as a small amount of some vegetable matter like duckweed.

The guppies need their own food of course, and I'd like to know what type of food chain I can create that doesn't rely on purchasing or importing feed of any kind. Commercial feeds for fish are typically made from ocean-caught "trash fish" and thus are likely contaminated with mercury or other heavy metals, which is why I'd like to avoid buying feed pellets. It's also expensive.

Several things I've considered for guppy food:

Daphnia
Paramecium
Algae (green water)
Mosquito larvae

Essentially, the only "free" inputs that are available are sunlight and oxygen (air). It seems like, in nature, that is enough to fuel the bottom of the food chain. So what is practical for a DIY system?

I don't know about Daphnia and Paramecium, but if you don't cover the guppy tank you'll get algae for sure. If you put a ring or some kind of separator around any aeration breaking the surface you'll probably get mosquito larvae in the still areas outside of it.

There are 15 asian freshwater clams in the guppy tank, acting as filters. It shares water with the rest of my AP system, so I'm not *too* concerned with an algae bloom because the clams clean the water a bit, but mostly my nitrate readings are 0's because I've got more demand from the plants than the system can currently satisfy.

Daphnia are filter feeders and eat bacteria and algae that are present in the water column. From what I've read, they tolerate low oxygen conditions pretty well so even in the event of an algae bloom in a standalone system, they should be okay.

So, kind of an update here:

I bought a culture starter for Daphnia Magna 'Russian Red'. The culture was split up between two 5-gallon buckets of tank water but for whatever reason the cultures essentially crashed slowly... there was no reproduction happening. Additionally the water became extremely funky and smelly since there was nothing eating the bacteria in it. I tossed everything.

At the same time that I ordered the daphnia culture online, I filled up a 12-gallon clear plastic storage tote with tap water, added 250mg of ascorbic acid to dechlorinate, and let it sit for a few days. I added a pinch of grass clippings from my neighbors lawn to the 12-gallon tote, as that was reccomended to get green water started. Well, lo and behold, somehow the grass clippings contained daphnia cysts/eggs. Fast forward a few weeks to today, and the culture has been running on autopilot and is thick with daphnia. 4-5 thousand at least.

My guppies also gave birth so I have about 60-70 baby guppies in that tank. I haven't noticed much cannibalism by the adults so I'm not bothering with separating them out. Both the baby and adult guppies *love* the daphnia, and mosquito larvae as well.

Additionally, I ended up buying a 50lb (22.6Kg) bag of soy flour and four pounds of yeast as a feed source for the daphnia. The green water might work but I don't have enough bright sunlight here.

I read you said that you have muscles and you arent worried about algae blooms.
They dont eat algae, they only eat detritus and the bacteria on it.
they will suck up algae, clean it and spit it out again.

If your beds are working properly, you shouldnt have to worry about pea soup algae blooms anyway, but stringy algae you will never stop if there is light.

My nitrates in my main system have been 0 ever since the seeds in the beds sprouted. Have had no algae issues at all. I have snails in both tanks, for better or worse (they came in on accident with a plant i bought). I imagine that catfish would eat stringy algae as well...yes? There's also duckweed "contaminating" the surface.

In any case, it looks like fish feed is going to need to be from a combination of sources. I don't foresee getting away from pelleted feeds completely anytime soon.

Pretty difficult to get away from having the pellets. Might be possible but much easier to reduce the amount needed by supplementing with other types of food.

I ended up ordering this yesterday, when it had free amazon prime shipping: http://www.amazon.com/gp/product/B00A7CYB4W?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00

Cost of feed pellets isn't what i'm concerned about so much as how they spoil if you overfeed. live food doesn't spoil

Truly, nature often works best when left to it's own devices. I have four 5-gallon translucent white plastic buckets full of water, that also happen to be full of daphnia. I seeded the buckets a few weeks ago with a few daphnia from the starter culture I got and the population exploded. I have not done any water changes -- I just let the water sit stagnant in the buckets and the daphnia love it. The water has been heavily clouded since I originally set the buckets up and just recently cleared up in two of the buckets, so I've added more activated yeast dissolved in water to provide some food.

The water in the other two buckets is still pea-soup green. But the daphnia population in those buckets are still terrific.

The daphnia magna are quite large, large enough in fact that I started feeding them directly to the channel catfish.

One question that remains to be answered is whether BSFL leachate / effluent can be added directly to either a daphnia culture or a greenwater tank.

You can also breed crickets, mealworms, vinegar eels, all sorts of critters of all sorts of sizes, with minimal effort, beyond initial setup. Crickets you can do with some soil, a ten gallon aquarium and an external heater, crickets (like 20 cents maximum, each) and you just feed them potatoes

Mealworms you just put in a bin with flour and they turn into beetles, breed, and die. Just make sure they can't get out.

raw potato for crickets?
water supply?

keep dirt damp?

what temp? 20c?



also, mealworms, people tend to put cut carrots in for moisture as far as i have seen.

For water potatoes usually are enough, yeah, just spritz the soil though, I use coco coir, um... I'm not sure what temp I just use an under tank heater. Mines like five watts I think. You can also get cricket food and water pillows from pet stores, I've used the food and gelatin stuff, never the water pillows, though I might try them out after I run out of this next jar. You can't have water in a dish because they'll down, for whatever reason. I think you could maybe do a something with a small bowl and Cotton balls but I'm not positive.

I also stick grasses, lettuce, blackberry leaves (they're an invasive species here) just general forage in for the crickets every few days. They might not be the healthiest crickets, but they seem to love potatoes, I cube it and keep them refrigerated, cleaning it once a week.