Fry Rearing Idea

HI everyone! I have developed an elaborate idea for breeding fish next year that will take advantage of the fact that my landlord only allows 20 gallons of tank inside the house but DOES allow water gardens on my back porch. Basically...I will breed the fish in a 1.5 gallon refugium attached to the parent's tank and start the fry indoors, but after about a week I will move the fry to larger quarters outside. The fry will be moved once they are either a week old or when they start taking microworms (whichever comes later) and, shortly thereafter, will start feeding the fry moina as well (first the young moina, which are about 80% the size of baby brine shrimp, then a mix of adults and juveniles). Here's some more details...forgive me, this is a lot of detail;

FRY SETUP
- Tank: Two 5 gallon buckets (with about 20 fry each), placed in a storage bin partially filled with water, attached to its own lid for stability (the lid will have a window cut out of it, with fine window screen over the window to keep bugs out) and equipped with a 300 watt heater (if needed). The bin, in turn, will be within a second bin filled with insulation.
- Filtration; Sponge filters, cleaned once a week. Will likely add beneficial bacteria after cleaning the sponge filter.
- Protocol; 40% water changes will be done at least once a day on each bucket. Fry will start on microworms; moina will be added as soon as possible, with fry powder being introduced within a few weeks of being moved outdoors. Fry will be rehomed/sold starting at the 3 month mark.

MICROWORM SETUP
- Containers; Two roughly 100 in^2 containers. Their normal lid will have a bunch of air holes cut in it, with filter foam placed over the holes to keep pests out.
- Media: 1 cup rolled oats, 2 cups water, and 1/2 tbs yeast
- Harvest protocol; Each Microworm culture will go for 14 days. On day 7 I will begin harvesting the culture by putting an unaltered lid tightly on the container, waiting 15 minutes, then collecting the worms that crawl up the sides seeking oxygen. Fish oil will be added about 6 hours before at least some hatches to improve the nutritional value of the worms. On day 14, the culture will be restarted. The two cultures will run on alternate schedules to ensure a steady supply of worms.

MOINA SETUP
- Containers; Two shallow bins (exact size undetermined, but will likely have about 5 gallons of water each) with the lids still attached. As with the fry bin, a window will be cut in the lid for ventilation, and the window will be covered with window screen to keep predatory insects out.
- Filtration; A sponge filter for each container.
- Harvest protocol; Batch cultures. Each setup will be started with about 5 gallons old aquarium water, to which I will add 5/4 tsp calcium carbonate, about 500 moina, and 1/4 tsp yeast. For the next 5 days the culture will be largely undisturbed except for stirring once a day to keep food in suspension. On day 6 I will check to see if moina densities have reached 10 moina per ml; if so, the moina will be enriched (what they will be enriched with is TBD) and, 6 hours afterward, be harvested, the culture being restarted as above. Again, cultures will be staggered to ensure a constant supply of moina. Some of the harvested moina will be immediately fed to my fish; the rest will be either frozen or refrigerated depending on my current needs. If refrigerated, moina will be fed for 6 hours to restore nutritional content before feeding to fish.

How does all of this sound? Thanks

 

HI everyone! I have developed an elaborate idea for breeding fish next year that will take advantage of the fact that my landlord only allows 20 gallons of tank inside the house but DOES allow water gardens on my back porch. Basically...I will breed the fish in a 1.5 gallon refugium attached to the parent's tank and start the fry indoors, but after about a week I will move the fry to larger quarters outside. The fry will be moved once they are either a week old or when they start taking microworms (whichever comes later) and, shortly thereafter, will start feeding the fry moina as well (first the young moina, which are about 80% the size of baby brine shrimp, then a mix of adults and juveniles). Here's some more details...forgive me, this is a lot of detail;

FRY SETUP
- Tank: Two 5 gallon buckets (with about 20 fry each), placed in a storage bin partially filled with water, attached to its own lid for stability (the lid will have a window cut out of it, with fine window screen over the window to keep bugs out) and equipped with a 300 watt heater (if needed). The bin, in turn, will be within a second bin filled with insulation.
- Filtration; Sponge filters, cleaned once a week. Will likely add beneficial bacteria after cleaning the sponge filter.
- Protocol; 40% water changes will be done at least once a day on each bucket. Fry will start on microworms; moina will be added as soon as possible, with fry powder being introduced within a few weeks of being moved outdoors. Fry will be rehomed/sold starting at the 3 month mark.

MICROWORM SETUP
- Containers; Two roughly 100 in^2 containers. Their normal lid will have a bunch of air holes cut in it, with filter foam placed over the holes to keep pests out.
- Media: 1 cup rolled oats, 2 cups water, and 1/2 tbs yeast
- Harvest protocol; Each Microworm culture will go for 14 days. On day 7 I will begin harvesting the culture by putting an unaltered lid tightly on the container, waiting 15 minutes, then collecting the worms that crawl up the sides seeking oxygen. Fish oil will be added about 6 hours before at least some hatches to improve the nutritional value of the worms. On day 14, the culture will be restarted. The two cultures will run on alternate schedules to ensure a steady supply of worms.

MOINA SETUP
- Containers; Two shallow bins (exact size undetermined, but will likely have about 5 gallons of water each) with the lids still attached. As with the fry bin, a window will be cut in the lid for ventilation, and the window will be covered with window screen to keep predatory insects out.
- Filtration; A sponge filter for each container.
- Harvest protocol; Batch cultures. Each setup will be started with about 5 gallons old aquarium water, to which I will add 5/4 tsp calcium carbonate, about 500 moina, and 1/4 tsp yeast. For the next 5 days the culture will be largely undisturbed except for stirring once a day to keep food in suspension. On day 6 I will check to see if moina densities have reached 10 moina per ml; if so, the moina will be enriched (what they will be enriched with is TBD) and, 6 hours afterward, be harvested, the culture being restarted as above. Again, cultures will be staggered to ensure a constant supply of moina. Some of the harvested moina will be immediately fed to my fish; the rest will be either frozen or refrigerated depending on my current needs. If refrigerated, moina will be fed for 6 hours to restore nutritional content before feeding to fish.

How does all of this sound? Thanks

What species of fish are you looking to breed, and where are you geographically? Post some pics here when the project gets underway.

 

What sort of fish do you plan to breed?

Many people have temperate to tropical fish in their outdoor ponds so that's not an issue. They generally add supplemental heat or bring the fish in during colder months weather depending.

I used to raise microworms in a jar on my office counter without issue. I used to start a new culture every ten days or so. Similar setup oatmeal and a pinch of yeast to feed them.

I wouldn't know a moina if it bit me, so I can't help you there. I did breed brine shrimp in a quart Mason jar and air stone setup, so there isn't really a need to over think culturing food stuffs.

It sounds like you are very keen to get going.

 

What species of fish are you looking to breed, and where are you geographically? Post some pics here when the project gets underway.

What sort of fish do you plan to breed?

Many people have temperate to tropical fish in their outdoor ponds so that's not an issue. They generally add supplemental heat or bring the fish in during colder months weather depending.

I used to raise microworms in a jar on my office counter without issue. I used to start a new culture every ten days or so. Similar setup oatmeal and a pinch of yeast to feed them.

I wouldn't know a moina if it bit me, so I can't help you there. I did breed brine shrimp in a quart Mason jar and air stone setup, so there isn't really a need to over think culturing food stuffs.

It sounds like you are very keen to get going.

I live in Northern New England, so fry raising would need to start in late May and would need to end by late September/early October (depending on the species being raised and the weather). The heater is in the event the fish being bred is a tropical fish...the season would be even shorter without one. I will be breeding my persian killifishes next year, but this could really be used for any reasonably sized fish (with modifications per species, of course...anabantoids, for example, would usually need infusoria before I can start with the microworms). The amount of live food produced will likely be far larger than what I need to raise the fry, so I will either freeze some of the live food or sell it to other hobbyists.

 

Best of luck! That sounds like quite the project!

 

Have you already used this recipe for growing micro worms. That seems to me like a lot of water. I put 1/2 cup water to 3/4 cup of oats for my cultures..

 

Have you already used this recipe for growing micro worms. That seems to me like a lot of water. I put 1/2 cup water to 3/4 cup of oats for my cultures..

I have not...it was a recipe recommended by an aquaculture article discussing the production and usage of microworms. Microworms are sufficiently unfussy (borderline extremeophilic...how many animals do you know that can breed in a PH from 1.6 to 11?) that LOTS of recipes will work...when I cultured microworms in the past I used a medium consisting of 1 part instant mashed potatoes to 2 parts water, and the roughly 5 by 3 inch cultures were ready to harvest in only 3 days.

 

I grow mine in a 4" square 3 1/2" high container. I used a sewing needle to punch super tiny holes in the lid. The holes are big enough to allow excess moisture to escape and oxygen in but small enough to keep flying pests out.

I start a new culture every 3 weeks and feed a pinch of yeast every 3 days. My new cultures start producing worms within 3 days of starting a new one. The old one is still producing lots of worms but I like keeping a fresh one.

I am afraid you will find that 2 cups of water to 1 cup of oats will be too much water. I don't know it for a fact but I think the worms would drown in that much water.

To harvest the worms I actually just use my finger to get them off the sides of the container. I used to use a q-tip but found it was more convenient just to use my finger and then just dip it in the fry tank to release the worms.

Doing it this way I do wash my hands well before and after feeding.

 

Maybe I will just use the instant mashed potatoes again then...those worked very well for me and did not have a particularly offensive odor.

 

Maybe I will just use the instant mashed potatoes again then...those worked very well for me and did not have a particularly offensive odor.

That sounds like a good idea. You know it works so no need to change to something that might not work as well for you.

 

HI everyone! Here's an update Yesterday I had my fish club meeting, and the speaker - a professor from UNH - gave a presentation about aquaculture. So, I have another idea I would like to run by you guys, based on what I heard...

The idea is an aquaponics system, with 3 tanks - one for growing terrestrial plants (most likely some kind of crop), one for the fry, and one used as a sump. Both the fry tank and the plant tank drain into the sump, which filters out particulate matter and converts ammonia into nitrate, which is subsequently consumed by the plants. This would require very few water changes (primarily top offs) and would allow a much higher density of fry than I initially planned; most of the work would be feeding the fry, cleaning the mechanical filtering media (perhaps a filter sock?), and occasionally adding iron (the one nutrient not produced in adequate quantities by fish food/waste). The main downside is that for ideal plant growth, nitrates would need to be maintained at about 150 ppm...obviously not all fish would appreciate that. What do you guys think of this?

EDIT...when I did further research, several sites recommended more modest nitrate levels around 40-80 ppm. Is that more reasonable for most freshwater fish?

 

around 40-80 ppm of nitrate, that would probably cause nitrate poisoning/ being lethal

 

around 40-
80 ppm of nitrate, that would probably cause nitrate poisoning/ being lethal

Oy...that is what I was afraid of oh well...good to know that now, before I accidentally poison any fry. Perhaps I can just try to grow houseplants hydroponically at a more reasonable 10-20 ppm.

EDIT: I did further research and found some papers on how nitrate levels affect freshwater fish and other life...for example; Nitrate toxicity to aquatic animals: a review with new data for freshwater invertebrates. - Semantic Scholar

This study found that nitrogen levels of 10 mg NO3-N (corresponding to about 44.3 ppm nitrate) over the long term negatively affects freshwater fish, amphibians, and invertebrates (surprisingly, the threshold for marine organisms was about twice that). The article recommended keeping particularly sensitive freshwater critters (fish fry?) no higher than 2 mg NO3-N (or about 8.86 ppm nitrate). I might just skip trying out aquaponics in that case, though the principles in that presentation could still be quite helpful.

 

I have been thinking, and I came up with a few modifications to my system. Here we go;

Fry raising setup; The fry will be raised in a 10 gallon tank/bin. The fry tank will drain into a sump where the nitrifying bacteria (and perhaps a few plants) will live; the sump will have a pump with a valve that directs a small part of the return water (less than 50 GPH) to a third container filled with clay hydroponics media, intended to grow the anaerobic denitrifying bacteria that convert nitrate to nitrogen gas. The denitrifying container will be sealed from oxygen except for the slow flow of water entering from the sump, and it will drain back into the sump. My goal is to be able to reduce water changes in the fry tank to once or twice a week while still maintaining nitrates no higher than 10 ppm and ideally below 5 ppm...is that feasible?

Microworms; Will split into 4 small cultures instead of 2 large ones. This makes it easier to harvest the worms multiple times a day and also makes it easier to add different enrichments to the worms.

Moina: May skip this, as by the time the fry are large enough to take adult moina I will be trying to get them on prepared foods.

 

I'm liking the Avenue you're going down with the aquaponic and hydroponic ideas. Eventually, it will be the norm for urban farming.
You'll need some hardy fish that can create a massive bio load to feed the crop. The fry alone will only produce a negligible amount.
Tilapia, Common Pleco and Gold fish are the key players that I can think of for this setup. Of course, a pond with 1000-2000gals would also be required. Do you have a garage to build this in and keep it out of the New England winter?

 

I'm liking the Avenue you're going down with the aquaponic and hydroponic ideas. Eventually, it will be the norm for urban farming.
You'll need some hardy fish that can create a massive bio load to feed the crop. The fry alone will only produce a negligible amount.
Tilapia, Common Pleco and Gold fish are the key players that I can think of for this setup. Of course, a pond with 1000-2000gals would also be required. Do you have a garage to build this in and keep it out of the New England winter?

Thanks I have neither a garage or anywhere else I can fit such a large setup, though...I live in an apartment with a 20 gallon tank limit and our back porch is about 7 by 4 feet. Since numerous lines of evidence suggest or imply that most fish can feel discomfort and pain, and since nitrate levels of 45 ppm are known to cause health problems for many freshwater fish, I don't think I am going to raise food fish in a true aquaponics setup.

HOWEVER, there is no indication that most aquatic invertebrates are similarly intelligent; thus, I have been thinking of setting up a small aquaponics setup using a dense Moina culture instead of using fish. How would that work?

 

Thanks I have neither a garage or anywhere else I can fit such a large setup, though...I live in an apartment with a 20 gallon tank limit and our back porch is about 7 by 4 feet. Since numerous lines of evidence suggest or imply that most fish can feel discomfort and pain, and since nitrate levels of 45 ppm are known to cause health problems for many freshwater fish, I don't think I am going to raise food fish in a true aquaponics setup.

HOWEVER, there is no indication that most aquatic invertebrates are similarly intelligent; thus, I have been thinking of setting up a small aquaponics setup using a dense Moina culture instead of using fish. How would that work?

I certainly agree about not consuming the fish. Tilapia would be the last fish I'd select to eat from a grocery store.
Will the dense moina culture produce enough nutrients to sustain something like basil?
Will this be a flood and drain style setup?

 

Actually, a 5gal bucket with a bubbler would be a quick and easy setup. A lid on top with a hole cut out to fit the plant pot, so the root tips just hang into the water.

 

I certainly agree about not consuming the fish. Tilapia would be the last fish I'd select to eat from a grocery store.
Will the dense moina culture produce enough nutrients to sustain something like basil?
Will this be a flood and drain style setup?

Perhaps...they eat phytoplankton, so they do best with lots of nutrients in the water. The moina would be in a 10 gallon setup that would drain into a sump (needless to say there will be a sieve over the drain to keep the moina out of the sump). The sump will contain the nitrifying bacteria and will capture solid wastes with a filter sock; a pump will then send half of the water back to the moina culture and half to the plant container, which will be filled with clay hydroponics media and will drain back to the sump. I would shoot for nitrates between 40 and 80 ppm...don't know how high they can get before harming moina, though.

EDIT: Some quick research revealed that Moina can continue to grow well at nitrate levels above 150 ppm, so nutrient levels should not be a problem.