Fish Stories: The aqua in aquaponics

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Fish Stories The “aqua” in aquaponics By Karen Swanberg [email protected] Summer '09

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Fish Stories: The aqua in aquaponics

Transcript of Fish Stories: The aqua in aquaponics

Page 1: Fish Stories: The aqua in aquaponics

Fish Stories

The “aqua” in aquaponics

By Karen [email protected]

Summer '09

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The Aquatic Component

● Fish and other species suited for the system– (covered in Class One, but slides are

appended)● Habitat needs● Water quality issues● Fish biology (too big a subject for this class)

– Will cover some basics of fish diseases and salt.● Food needs and sources● Fish growth rates

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Habitat● Solitary fish often

need lots of places to hide, and most fish will be less stressed if they can hide part of the time.

● Hides can include plant life, big rocks, wood and PVC pipe.

● Schooling fish tend to need more room.● Some fish, like catfish, need a substantial

amount of horizontal room in order to breed.

© dailymail.co.uk

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Water Quality issues - Important tank parameters

● pH● Temp● Nitrogen● Mineral hardness● Oxygen● Chemicals

– Chlorine/chloramine/metals etc.

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Chemical Tests

© Jethro Hanson

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© Bootsy on the BYAP forum

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PH scale

From WikipediaLog scale

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Tap water pH: it changes with age● When water comes out of the tap, it's usually

very poorly oxygenated and high in carbon dioxide (CO

2). The carbon dioxide forms a weak

acid, so the pH of the water will be artificially low.

● As the water ages, the CO2 outgases, and

therefore the pH rises (gets more alkaline).● When you first start, test the pH of the water

right out of the tap, then age it a few days and test it again.

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pH, cont...● Shoot for a neutral (7) pH.● It's a good balance between fish, plant and

bacteria requirements.● High or low pH will affect what can grow in the

system, and how the plants take up nutrients.● Having said that, I know of systems that run as

low at 6.0 and as high as 8.0● Lemon juice (acid) lowers pH, Baking Soda

(base) raises it.

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pH, cont...● Adding shells [or other Calcium Carbonate

(CaCO3)] to the system will buffer the pH to

the mid 7's, and is a common way to control pH.

● As a bonus, the shells will add micronutrients.

● The bacteria will tend to lower the pH over time.

● Always adjust pH SLOWLY.● Fast changes in pH kill fish.

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pH vs Nutrient Uptake

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Temperature

● The temp of the water affects how much oxygen it can hold – the warmer the water, the less oxygen.

● The temp of the water affects how the fish deal with nitrogen, especially Ammonia.

● All fish have a comfortable range.● Some fish need specific temps to breed.

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Temp, cont...

● Lots of docs talk about celsius. Easy to convert online.

● In google search, type “convert 4f to c” and it will give you the answer.

© Harriet P.http://goscandinavia.about.com/od/weatherinscandinavia/qt/tempconversion.htm

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The Nitrogen Cycle

© Backyard Aquaponics Magazine, vol 1

● It's all about the bacteria:

● Nitrosomonas sp.

– NH4 → NO

2

● Nitrobacter sp.

– NO2 → NO

3

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Bacteria● Like to live on a surface● Reproduce rapidly● Need good oxygen levels in the water● “As a general rule, a brand new system will take about 4

weeks to cycle at around 68*F.● Colder temps take longer.● Dryness and temps above 120*F kill the bacteria, as does

freezing.● Nitrosomnas sp likes pH 7.8 – 8.0● Nitrobacter sp. Likes pH 7.3-7.5

Info from Backyard Harvest Magazine, vol. 1

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Nitrogen: Ammonia (NH4)

● Fish excrete ammonia, but ammonia is toxic to fish.● Damages tissues, esp. gills and kidney● Impairs growth● Decreases resistance to disease● Can kill.

● Also produced by excess food and dead fish.● Toxicity depends on water pH and

temperature.

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Nitrogen: Ammonia (NH4)

The warmer the temperature, and the higher the pH, the more toxic the ammonia.

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● Less toxic than ammonia, but can still kill● Stops fish from absorbing oxygen● Toxicity can be controlled with salt (more later)

Nitrate (NO3)

● One of the major plant nutrients● A level of 0 means the plants are using it all● Safe levels are about 0 - 40

Nitrite (NO2)

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Mineral hardness (hard water)● Hard water is water that has high mineral

content (mainly calcium and magnesium ions, but sometimes others).

● Two types of hardness:– alkalinity (often referred to as carbonate or

temporary hardness)– permanent hardness

From BYAP forum, “water hardness and fish health”and http://en.wikipedia.org/wiki/Water_hardness

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Alkalinity● Not the same thing as high pH!● Alkalinity refers to the hardness derived mainly

from carbonate and bicarbonate ions and directly reflects the buffering capacity of the water.

● This form of hardness is also called carbonate hardness or temporary hardness because it can be precipitated and removed by boiling the water. Which is why lime-scale forms in kettles and showerheads!

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Permanent Hardness

● Permanent hardness measures the ions such as nitrates, sulphates, and chlorides etc, that are not removed by boiling.

● Most of these are not involved with buffering but can affect pH values.

© http://www.ceasa.co.in

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Hardness, cont...

● As a rule of thumb, hard water is usually well buffered while soft water is usually less well buffered.

● This can be inaccurate, depending on conditions.

● Water tests are available for both types of hardness.

● Hardness is another good reason to put sea shells in your system (or grit, egg shells etc.)

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Oxygen● Fish, plant root and bacteria all need decent O

2

levels.– Flood and drain through gravel or substrate– Water falling– Aerators

● Fish O2 needs vary

● Tests are available.

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Chemical Contaminants● Chlorine and Chloramine

– Added by municipalities– Get rid of it by adding drops

● From pet store, or bulk sodium thiosulphate (ebay)● http://www.cnykoi.com/calculators/calcstdose.asp

– Chlorine can be aerated out of water, chloramine can not (mostly)

© Foster and Smith

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Other contaminants

● Copper is harmful to some fish and fatal to crustaceans.

● Some drops can also neutralize heavy metals.● When all else fails, go to a reverse osmosis

filter. Very very expensive, but does the job.● (Doctors Foster and Smith sells RO for $100 –

$500, depending.● http://www.drsfostersmith.com

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Fish Diseases

● For the most part, fish medications are not safe for humans to eat.

● Do not medicate fish while in an AP system– Put the fish in quarantine

● If you want to eat the fish, the main treatment is salt.

● High concentrations of salt should also be used only in a quarantine system.

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Fish diseases● Ammonia/nitrite poisoning● Temp issues● Bacterial infections

● Includes fin and tail rot● Fungal infections● Parasites

● Internal– Hole in head disease

● External– Ich or whitespot– Gill flukes

© Foster and Smith

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© JBL - Online Hospital

© my-tropical-fish.com

© aquariacentral.com

Hole in Head disease

Ich (whitespot)

Finrot

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http://www.drsfostersmith.com/pic/article.cfm?c=3578&articleid=1338&category=583

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Salt, the AP cure-all● Helps against nitrite toxicity● Reduces fish stress (helps with

osmotic pressure)● Killing off parasites (ich)● Short, strong salt dips/baths can

help healing wounds or parasites (also common practice with new fish before introducing them into general population)

© API

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Salt, cont...

● Use sea salt or sun-dried salt.● Sea salt also contains lots of micronutrients

● Do NOT used iodized salt, or salt with other additives to make it a pellet or anything.

● Solar water softener salt is cheap and easy to get in big bags.

● Pool salt from pool supply stores will also work.

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When to use salt

● Some people have salt in their systems all of the time, up to about 3 ppt (parts per thousand)

● Higher concentrations can be used for short dips or baths to treat fish with injuries.

● Salt will kill some plants– Strawberries die at very low concentrations of

salt, but most plants are OK up to about 3ppt.

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How much salt?

● Salt concentrations are measured in parts per thousand (ppt).

● 1 kilogram (kg) of salt in 1000 liters of water = 1ppt.

● That comes out to about 1/3 lb of salt for every 40 gals of water.

● Or 3.8 grams of salt into 1 gal of H20 = 1ppt

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Fish food

● As always, needs differ. Some fish are carnivorous (trout, barramundi), omnivorous (tilapia, catfish) and herbivorous (plant nibblers and grazing fish, like plecos).

© funfishtanks.com

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Fish food sources

● Nutritional needs differ, but all fish need a balanced diet. You can't live on weeds alone.

● To start, it's probably best to go with a commercial food.

– I now buy mine in 50lb bags, which last me about a year.

● Grow your own:– Vermicomposting worms, black soldier fly

larvae, other insects (hang a bug zapper above the tank?), duckweed, other plant matter.

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Fish Growth rates

● This is usually discussed as “Feed Conversion ratio” or “Feed efficiency.”

● For instance, tilapia are often quoted as having a rate of roughly 1 : 1.5

– with a feed conversion ratio of 1.5, the fish would gain 10 grams for every 15 grams of feed

● Will depend on feeding frequency, type of food, water conditions and other factors.

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Questions?

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Resources● JBL Online Fish Hospital

● http://www.jbl.de/?lang=en● Good fish health search, via picture or text

● http://www.byapmagazine.com● Backyard Aquaponics magazine. Good, well-written, thorough articles.

First Edition is free.

● The collection of “Useful Information” articles on BYAP:● http://www.backyardaquaponics.com/forum/viewforum.php?f=11

● Water Hardness and Fish Health● Salting for Fish Health● Ammonia – The Silent Killer● etc.

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Resources, cont...

● Doctors Foster and Smith● Good online store, good selection, good articles

and is in Wisconsin, so less shipping distance.● http://www.drsfostersmith.com

● Aquatic Ecosystems● Another good online store, tends to be a bit more

industrial than Foster and Smith● http://www.aquiaticeco.com

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Resources, cont...● Miami Aquaculture

● Online source for tilapia. Mixed sex and all-male fingerlings, only in bulk, but breeders available individually

● Multiple breeds of tilaia, including the hybrid Rocky Mountain White, which is cold(er) hardy.

● http://www.miami-aquaculture.com● R&D Aquafarms, Inc.

● All-male tilapia fingerlings available in small batches. In Oshkosh, WI.

● http://www.rdaquafarms.com

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Fish!● A critter that lives in water that produces

ammonia or other source of nutrient.● Common:

– Tilapia– Perch– catfish

● Cool!– snails (be careful of the pump)– Crawdads/crayfish/yabbies/redclaw– Shrimp, mussels, eels, other.

● Ornamentals– koi, tropical fish

Photo © BYAP

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Fish considerations

● Ease of care● What do they eat?● What temperature water do they require?● Are there special water requirements?

– pH, salinity, hardness● Rate of growth / efficiency of food -> growth

conversion● Are they tasty, my precious?● Do you enjoy them?

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● Most people start with goldfish – cheap, hard to kill, eat anything.

● Once you get a feel for the system and how it works, expand to a fish more suitable to your conditions.

● Do you want to heat a tank all winter?● Do you want to grow fish out to eating size in 9

months?● Are they legal in your state? (tilapia are illegal in

some southern states).● Native, local fish are often a good choice.

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Be prepared to become a Be prepared to become a serial fish killerserial fish killer

Photo ©Joel Malcolm & BYAP