Aquaponics FL

Fish · Ornamental fish

Koi in Florida aquaponics

Cyprinus carpio

Koi are a colored, ornamental form of the common carp: a hardy, nonnative coolwater fish that some aquaponic systems keep for their waste and their looks rather than for food. They do best at about 65 to 75 F, so Florida's long hot season is the main stress, and newly bought koi can bring in koi herpesvirus, so quarantine matters. FWC's general rule on nonnative fish and its aquaponics guidance read differently for a fish like koi; ask FWC before stocking.1, 2, 4, 6, 7

Where in Florida it works1

RegionReading
North Floridawell suited
Central Floridasuited with care
South Floridasuited with care

Our reading, not a source statement: SRAC 7201's survival range of 32 to 95 F means North Florida winters, which freeze most years, fall within what koi tolerate, and its 65 to 75 F best range fits North Florida's cooler months. Summer water anywhere in Florida, and much of the year in tropical South Florida, is likely to sit above that best range, so shade, depth and slow temperature changes matter more the farther south you are.

Our reading of the temperature facts below against UF/IFAS's three regions (North Florida north of State Road 40, Central between 40 and 70, South below 70). A tank with a heater, a greenhouse or a shaded sump changes the answer.

Temperature1, 2, 3

Optimal water temperature (°F)65 to 75

SRAC 7201: koi and goldfish are temperate fish with a best range of about 65 to 75 F (18 to 24 C). They can survive water as cold as 32 F and as warm as 95 F, especially when the change is gradual and seasonal, but outside the best range they eat and grow less and their immune systems weaken. Disease windows: VM-149 says koi herpesvirus outbreaks usually occur at 60 to 77 F, can kill up to about 82 F, and infect without signs near 55 F; VM-142 says spring viremia of carp deaths mostly occur between 11 and 17 C (converted: about 52 to 63 F) and decline above 22 C (converted: about 72 F).

Florida rules1, 3, 6, 7, 8, 9, 10, 11, 12

FWC statusKoi are an ornamental variety of the common carp, which SRAC 7201 says is native to Eurasia, so koi are not native to Florida. Common carp and koi do not appear on FWC's Conditional Nonnative Species List or Prohibited Nonnative Species List as fetched; the Conditional list's carp entries are grass, silver, bighead and black carp. FWC's nonnative species regulations page states Rule 68-5.001: "It is unlawful for any person to possess, transport or otherwise bring into the state or to release or introduce in the state any freshwater fish, aquatic invertebrate, marine plant, marine animal, or wild animal life that is not native to the state without a permit from the Commission, except fathead minnow, variable platy, coturnix quail, and ring-necked pheasant." FWC's Aquaponics Licenses & Permits page, by contrast, says "No permit needed if aquatic species are produced for personal use only (not sold) and acquired in Florida". The two pages read differently for a nonnative fish such as koi; neither names koi or explains how the rule applies to pond or aquarium fish. This is a question for FWC and is not resolved here. FWC pages show no revision date; read 2026-11-02.
Permit or certificateNo fetched page names a permit for koi. See the two FWC statements above. FWC's aquaponics page lists a "Resident Fish Dealer's license if purchasing fish from sellers outside Florida" for personal-use systems. A commercial aquaponic business producing and selling aquatic animals needs an FDACS Aquaculture Certificate of Registration (FDACS-P-01770 Rev. 12/25).
Selling fish or fingerlingsFWC's aquatic-species regulations page says commercial fish dealer's licenses are required "to sell nonnative fish and frogs in Florida". FWC's aquaponics page lists a "Resident fish dealer's license (RFD) issued by FWC if selling live fish to the public". Certified farms must follow FDACS's BMPs, which require holding, transport and culture systems to prevent the escape of all life stages of nonnative aquatic species into waters of the state (FDACS-02034 Rev. 11/2023).
AlsoFWC's aquaponics page: "It's illegal to release any nonnative species in Florida." and "Aquatic species that are left over from aquaponics projects may not be released into Florida waters." Spring viremia of carp, which infects koi, is reportable to USDA and is on Florida's list of reportable animal diseases (VM-142).

Rules change and this is a summary; the agency page in the sources is the authority. Check it before you buy, breed or sell.

Growing1, 2, 5

Harvest sizeset by the market; koi are sold by size, color, pattern and finnage rather than by weight
Months to harvest3 to 4 for small feeder fish; about 12 for many ornamentals; more than 12 for the deep red color of some koi
StockingSRAC 7201 gives no stocking density. For any small aquaponic system, SRAC 5007's general guide for new growers is a final density of about 1 pound of fish per 10 gallons.
FeedSRAC 7201: most producers use a 25 to 32 percent protein feed through grow-out, moving from a fine meal up to about a 1/4-inch pellet. Carp have no true stomach, so several feedings a day help. Pigment-rich diets improve color. In tanks, use complete feeds. SRAC 5007 says koi may need as little as 22 percent protein.
Water qualitySRAC 7201: dissolved oxygen at least 5 mg/L (koi tolerate less for short periods); un-ionized ammonia and nitrite below 0.05 mg/L; pH as close to 7 as possible, though koi tolerate 5 to 9.

Koi are hardy but prone to anchor worm, fish lice, gill and skin flukes, and protozoans such as Ich, Trichodina and Chilodonella, especially in poor water. Koi ulcer disease, often caused by Aeromonas salmonicida, can kill up to half a population and is most common at 55 to 75 F after spawning or handling (SRAC 7201). There is no treatment for koi herpesvirus; quarantine new koi in a separate system at 75 F for at least 30 days, with their own nets and buckets (VM-149). Goldfish can carry koi herpesvirus to koi without showing signs (VM-149). Common carp can grow past 4 feet and 80 pounds and live at least 50 years (SRAC 7201).

Breeding and stock1, 7

How it breedsSRAC 7201: koi mature at 1 year, but commercial brood fish are usually at least 2 years old. They spawn in spring, February to May depending on location, as water nears 68 F; keep sexes apart until then to prevent unplanned spawning. Several males chase each female and fertilize the sticky eggs, which naturally land on plants at the water's edge, so producers use spawning mats and move them away quickly because the adults eat the eggs. Hormone injections (HCG, carp pituitary extract, LHRH or GnRH) at 68 F bring ovulation within 12 hours. Eggs hatch in 46 to 54 hours at 84 F and 5 to 7 days at 70 to 75 F; fry start feeding on the second or third day and take brine shrimp nauplii right away.
Getting fingerlings or stockSRAC 7201 says most U.S. koi production is cheap, high-volume wholesale fish, with a smaller number of specialty producers selling fish for hundreds of dollars each. Brood quality decides offspring quality: inexpensive koi give very mixed offspring, and in high-end lines up to 90 percent of fish may be culled. FWC's aquaponics page says buying fish from sellers outside Florida for a personal system needs a Resident Fish Dealer's license.

Florida sellers of fingerlings, breeders and stock

In an aquaponics system4, 5

suited with care

SRAC 454 lists koi carp among species aquaponic systems have used and says most crowding-tolerant freshwater fish, ornamentals included, do well. SRAC 5007 notes koi can live on lower-protein feed. The same sheet warns that without a fish harvested for food or sold to offset costs, a plain hydroponic system is usually cheaper to run, so koi make sense in aquaponics mainly as ornamental or sale fish. Heat and the unresolved FWC permit question are the main cautions in Florida. The FAO aquaponics manual could not be fetched.

On the table1, 2

The fetched sources treat koi as ornamental or feeder fish, not food. VM-149 notes that the common carp, the same species, is raised as a food fish in many countries.

What this page doesn't cover yet

  • FWC's Rule 68-5.001 wording (permit needed for any nonnative freshwater fish, with four named exceptions) and FWC's aquaponics page (no permit for personal use if acquired in Florida) read differently for koi, and no fetched FWC page names koi, goldfish or carp in this context. Needs an answer from FWC.
  • SRAC 7201 gives survival limits (32 F and 95 F with gradual change), not lethal temperatures or a point where growth stops; those fields are null.
  • No source gives an aquaponic stocking density for koi.
  • Sources disagree on koi herpesvirus: SRAC 7201 (2004) gives 64 to 81 F as the usual outbreak range, says it affects only koi and is not reportable; EDIS VM-149 (revised June 2025) gives 60 to 77 F, says goldfish can carry and spread it, and says KHV has been on the WOAH list since 2007, with USDA asking veterinarians and labs to report cases.
  • Sources differ on spring viremia of carp temperatures: SRAC 7201 says it is more common at 41 to 64 F (5 to 18 C); EDIS VM-142 says deaths mostly occur at 11 to 17 C.
  • The FAO 'Small-scale aquaponic food production' manual returned HTTP 403 on every FAO URL tried, so it was not used.
  • The EDIS HTML page for VM-149 (ask.ifas.ufl.edu/publication/VM113) failed with too many redirects; the PDF was read instead.

Sources

  1. Species Profile: Koi and Goldfish. Southern Regional Aquaculture Center (SRAC); authors at UF/IFAS Tropical Aquaculture Laboratory, SRAC 7201. Read 2026-11-02.
  2. Koi Herpesvirus Disease (KHVD). UF/IFAS Extension, EDIS, VM-149. Read 2026-11-02.
  3. Spring Viremia of Carp Virus (SVCv). UF/IFAS Extension, EDIS, VM-142. Read 2026-11-02.
  4. Recirculating Aquaculture Tank Production Systems: Aquaponics—Integrating Fish and Plant Culture. Southern Regional Aquaculture Center (SRAC), SRAC 454. Read 2026-11-02.
  5. Principles of Small-Scale Aquaponics. Southern Regional Aquaculture Center (SRAC), SRAC 5007. Read 2026-11-02.
  6. Nonnative species regulations. Florida Fish and Wildlife Conservation Commission. Read 2026-11-02.
  7. Aquaponics Licenses & Permits. Florida Fish and Wildlife Conservation Commission. Read 2026-11-02.
  8. Conditional Nonnative Species List. Florida Fish and Wildlife Conservation Commission. Read 2026-11-02.
  9. Prohibited Nonnative Species List. Florida Fish and Wildlife Conservation Commission. Read 2026-11-02.
  10. Nonnative species regulations: aquatic species. Florida Fish and Wildlife Conservation Commission. Read 2026-11-02.
  11. Commercial Aquaponics: Rules and Regulations. Florida Department of Agriculture and Consumer Services, Division of Aquaculture, FDACS-P-01770 Rev. 12/25. Read 2026-11-02.
  12. Aquaculture Best Management Practices Manual (incorporated into Rule 5L-3.004, F.A.C.). Florida Department of Agriculture and Consumer Services, Division of Aquaculture, FDACS-02034 Rev. 11/2023. Read 2026-11-02.

Every fact above is restated in our own words from these documents, written 2026-11-02. Independent of the University of Florida and of every agency named.

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