- Compare fish by purpose and temperature.
- Separate survival from a productive operating range.
- Prepare an exact-species procurement and care plan.
Fish comparison tool
Filters match a published planning band, not survival limits or stocking permission. Confirm exact species, hatchery requirements and local rules. Temperature alone cannot establish suitability.
6 temperature / purpose candidates
Tilapia
23.3–26.7°C / 74–80°FWarm, stable systems with an available lawful seedstock supply.
OSU HLA-6721 lists 74–80°F optimum; NMSU CR680 gives 81–85°F for maximum growth and notes growth slows dramatically below 70°F. Heating demand in cool seasons; breeding and size variation need management. Confirm the exact species/strain.
Planning-band source ↗Trout
12.8–18.3°C / 55–65°FReliably cool water and strong oxygen delivery.
Higher oxygen requirement; warm weather and cooling failure can dominate the design. Identify trout species and hatchery requirements.
Planning-band source ↗Catfish
23.9–29.4°C / 75–85°FWarm-water production with good bottom access and solids collection.
“Catfish” covers multiple species. Confirm hatchery stocking, growth and handling guidance.
Planning-band source ↗Bass
23.3–26.7°C / 74–80°FExperienced operators with suitable stock and market.
Predatory behavior, size grading and feed acceptance complicate mixed groups. Identify species before design.
Planning-band source ↗Goldfish
18.3–23.9°C / 65–75°FAn ornamental or teaching system without a food-fish harvest goal.
Still requires mature filtration, oxygen, welfare and a long-term home; not disposable cycling stock.
Planning-band source ↗Koi
18.3–23.9°C / 65–75°FLong-term ornamental systems planned around mature fish.
Large adult space and handling needs; plan lifetime biomass, quarantine and secure containment.
Planning-band source ↗01 / Choose the fish before the stocking number
Start with the water temperature you can maintain throughout the year, the purpose of the fish and the stock you can obtain lawfully from a reputable source. A fish that survives a short temperature excursion is not necessarily growing or feeding well there.
The table uses published planning bands, not lethal limits. “Trout,” “bass” and “catfish” are broad common names: exact species, strain, age and hatchery guidance must refine the design. Do not assume a pet-store fish or locally caught fish is suitable food-production stock.
Reading: Aquaponics (HLA-6721) ↗ · Fish Health Management Considerations in Recirculating Aquaculture Systems—Part 3 ↗
02 / Compare candidate groups
OSU’s introductory table supplies all six temperature bands below. NMSU CR680 describes a warmer 81–85°F band for maximum tilapia growth and notes growth slows sharply below 70°F; different references use different objectives, and the difference is kept visible rather than averaged into a false universal optimum.
| Candidate | Purpose | Published planning water band | Feed / constraint |
|---|---|---|---|
| Tilapia | Food | 74–80°F (23.3–26.7°C) | Species- and size-appropriate complete tilapia feed. OSU HLA-6721 lists 74–80°F optimum; NMSU CR680 gives 81–85°F for maximum growth and notes growth slows dramatically below 70°F. Heating demand in cool seasons; breeding and size variation need management. Confirm the exact species/strain. |
| Trout | Food | 55–65°F (12.8–18.3°C) | Complete trout feed matched to life stage. Higher oxygen requirement; warm weather and cooling failure can dominate the design. Identify trout species and hatchery requirements. |
| Catfish | Food | 75–85°F (23.9–29.4°C) | Complete aquaculture feed for the selected species and size. “Catfish” covers multiple species. Confirm hatchery stocking, growth and handling guidance. |
| Bass | Food | 74–80°F (23.3–26.7°C) | Species-appropriate pellets; confirm fish are feed trained. Predatory behavior, size grading and feed acceptance complicate mixed groups. Identify species before design. |
| Goldfish | Ornamental | 65–75°F (18.3–23.9°C) | Complete feed suitable for the stock, sized to mouths. Still requires mature filtration, oxygen, welfare and a long-term home; not disposable cycling stock. |
| Koi | Ornamental | 65–75°F (18.3–23.9°C) | Complete koi feed appropriate to size and temperature. Large adult space and handling needs; plan lifetime biomass, quarantine and secure containment. |
Reading: Aquaponics (HLA-6721) ↗ · Important Water Quality Parameters in Aquaponics Systems (CR680) ↗
03 / Check the conditions together
NMSU describes about 5 mg/L dissolved oxygen for warmwater fish and about 6.5 mg/L for coldwater trout health and growth. These are source planning references, not alarm thresholds for every species and loading. Confirm operating and emergency limits with the stock supplier or aquaculture specialist.
Temperature influences oxygen capacity, feed intake, waste production and crop fit simultaneously. Tilapia heating and trout cooling can dominate energy use. A cool-water fish system and warm-season basil do not necessarily share an efficient operating point.
Reading: Important Water Quality Parameters in Aquaponics Systems (CR680) ↗
04 / Write a stocking specification
Before buying fish, obtain the scientific name, size range, health history, feed type and size, temperature guidance, transport method and applicable local requirements. Plan quarantine with separate equipment, filtration and water; a spare uncycled bucket is not quarantine capacity.
Use the feed-balance chapter to model a planned ration and growing area, then separately verify fish-tank, oxygen and biofilter capacity. Do not increase fish numbers just because plant leaves look pale.
- Log realistic seasonal water temperatures and the cost of controlling them.
- Shortlist fish by purpose, exact species, hatchery availability and local permission.
- Confirm complete feed availability and appropriate pellet sizes through the growth cycle.
- Prepare a cycled quarantine and a supplier-specific transport/acclimation plan.
- Stock conservatively within the verified system design, observe closely and increase loading only after stable measurements.
Reading: Fish Health Management Considerations in Recirculating Aquaculture Systems—Part 3 ↗
05 / Plan the endpoint
Food fish need a lawful, humane harvest and handling plan before they outgrow the system. Ornamental fish need space and care at mature size, even when their role is to support plant nutrition. Never release unwanted fish into waterways.
The comparison tool filters only the published temperature bands and purpose. A match is a candidate for further design, not a species recommendation or permission to stock. No match is useful evidence that the temperature plan needs reconsideration.
FIELD QUESTIONWhy is “hardy fish” an incomplete purchasing criterion?
Tolerance does not establish good growth, welfare, feed conversion, legal availability or suitability for your seasonal water temperature and treatment capacity.
Parts & buying criteria
Build your own parts & cost worksheet →
Showing aquaponic raft system. Quantities describe the teaching model. Specify real working volume, support, fittings and instruments for your installation.
01Fish tank1 · illustrated quantity+
Houses fish and receives the pumped return. Feed is an input to this living system.
Inspect: The fish are generic silhouettes, with no species or stocking-rate recommendation. Cutaway reveals the tank interior.
Maintain: Observe behavior and feeding response; keep a record of water tests and changes.
Smooth accessible tank, secure cover and species-appropriate volume determined by an aquaculture design.
Check size, materials and operating conditions with your chosen supplier before ordering.02Solids separator1 · illustrated quantity+
Intercepts settleable waste before it accumulates in later treatment and growing components.
Inspect: Open the front of the vessel. Brown particles beneath the central baffle represent collected waste, not a settling simulation.
Maintain: Inspect accumulation and remove it on an observation-based schedule without flushing it into the growing bed.
Accessible waste drain, removable internals and a design matched to expected solids and flow.
Check size, materials and operating conditions with your chosen supplier before ordering.03Biological filter1 · illustrated quantity+
Provides wetted surface for nitrifying organisms. This teaching layout shows a separate biofilter.
Inspect: The blue carriers indicate surface area; cyan flow does not measure nitrification or oxygen availability.
Maintain: Protect the established community during service. Verify nitrogen readings before and after changing loading or equipment.
Media and aeration matched to the intended feed load, water conditions and an independently reviewed design.
Check size, materials and operating conditions with your chosen supplier before ordering.04Raft growing bed1 · illustrated quantity+
Holds plants above water after solids handling and biofiltration. Roots hang below the raft.
Inspect: Compare the depth of this growing section with the shallow channels in the hydroponic lesson.
Maintain: Keep drains accessible and inspect root congestion. Remove crop debris without sending it downstream.
Cleanable bed, supported raft, access to drains and a root-zone aeration plan.
Check size, materials and operating conditions with your chosen supplier before ordering.05Sump & return pump1 · illustrated quantity+
Collects gravity drainage and pumps water to the fish tank, closing this particular circuit.
Inspect: This is the lowest collection point. The tank, filters and bed have progressively lower illustrative water levels.
Maintain: Check sump level, intake and leaks. Test whether drainage can be contained when power stops.
Usable reserve volume, pump service access, level protection and verified delivery at the required head.
Check size, materials and operating conditions with your chosen supplier before ordering.06Air supply1 · illustrated quantity+
A separate air pump supplies diffusers to the fish tank, biofilter and growing bed.
Inspect: White bubbles indicate air delivery only; bubble count is not a dissolved-oxygen reading.
Maintain: Check air lines, diffusers and backup arrangements. Verify oxygen with suitable measurement.
Airflow at operating depth, compatible diffusers and resilience reviewed for the living load.
Check size, materials and operating conditions with your chosen supplier before ordering.Evidence beside the lesson.
Source checks: September 2026. The geometry, inspection exercises and worksheets are original teaching material. The named organizations have not endorsed or reviewed this site.
Published recipe rates and planning ranges retain their source context. Calculator equations are accounting tools; they do not predict uptake, yield, toxicity or safe stocking. Model dimensions, water speeds, roots and fish counts are illustrative. Verify species, crop, source water and product labels for a real system.
- Oklahoma State University ExtensionAquaponics (HLA-6721) ↗
Coupled fish, microbes and plant needs.
- University of Florida IFAS ExtensionFish Health Management Considerations in Recirculating Aquaculture Systems—Part 3 ↗
Biosecurity, quarantine, health monitoring and diagnosis.
- New Mexico State University ExtensionImportant Water Quality Parameters in Aquaponics Systems (CR680) ↗
Fish-system water chemistry, oxygen, temperature and nitrification.
The next useful connections.
Feeding, biomass and stocking
Use fish mass and actual feed intake as operating inputs, with capacity checked independently.
Interactive tool · 6 min + guided practice →Cycling & water balanceBalance fish feed and planted area
Turn feed grams per day into a transparent area comparison, then check the biological and hydraulic limits.
Interactive tool · 6 min + guided practice →Operation & resilienceFish health, quarantine and daily operation
Prevent avoidable introductions, observe fish before symptoms escalate and keep records useful for diagnosis.
6 min + guided practice →ComparisonsTilapia, trout or catfish: choose by the water you can hold
Choose between three food fish by the water temperature you can hold through the year, then follow the choice through oxygen, energy, legality and crops.
Interactive tool · 8 min + guided practice →