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ARMORTHANE PROTECTING YOUR WORLD

PROTECTING YOUR WORLD

ARMORTHANE PROTECTING YOUR WORLD

Aquaculture Tank
Coatings: Fish-Safe
Linings

How to line concrete, steel and fiberglass fish tanks, raceways and ponds with a seamless, fish-safe coating, what to check before stocking, and where spray polyurea fits.
Aquaculture Quotes

Leaking or rough tanks? Get them lined.

Tell us about your tanks, raceways or ponds. We will connect you with a certified applicator who can quote a fish-safe lining.

  • Tank type and material
  • Number and size of tanks
  • Freshwater or saltwater
  • Species and stocking date
Rather talk now? Call (417) 831-5090
Step 1 of 3
Full cure
Before any water contact with fish
Product data sheets
NSF 61
Potable-water certification many specs use
NSF/ANSI/CAN 61
Smooth
Surfaces protect fins and clean easily
Industry practice
Seamless
No joints to leak or harbor growth
Spray polyurea

Fish farms, hatcheries and research facilities depend on tanks and raceways that hold water, clean easily and never leach anything harmful into the water. Bare concrete is rough and porous, steel corrodes and old fiberglass blisters. A fish-safe lining fixes all three, but only if the product, cure and rinse are right. This guide explains how aquaculture tank coatings work and what to check before you put fish back in the water.

Quick answer

An aquaculture tank coating is a seamless lining applied to concrete, steel or fiberglass fish tanks, raceways and ponds to stop leaks, protect the structure and give fish a smooth, cleanable surface. Choose a product that the manufacturer documents as suitable for aquatic life, often one certified to NSF/ANSI/CAN 61 for drinking water contact, apply it to the specified thickness, let it fully cure, then fill, flush and test the water before stocking. Spray polyurea is popular because it cures in seconds and builds a thick, flexible, seamless membrane.

What's in this guide
  1. 1What fish safe means
  2. 2By tank type
  3. 3Lining options
  4. 4Lining process
  5. 5Why polyurea
  6. 6FAQ
Start here

What "fish safe" really means

There is no single "fish safe" label. In practice, it means the cured coating does not leach substances that harm fish or invertebrates. Many facilities use products certified to NSF/ANSI/CAN 61, the drinking water contact standard, as a starting point, then follow the manufacturer cure time and a fill-and-flush before stocking. Sensitive species, hatcheries and research systems may add their own water testing.

Product

Documented product

Use a product the maker supports for aquatic or potable service. See AquaSafe pure polyurea.

Cure

Full cure

Uncured material is the main risk. Follow the cure time and temperature on the data sheet.

Flush

Fill and flush

Fill, circulate and drain before stocking, and test water quality.

Where it fits

Linings by tank type

Concrete

Concrete tanks and raceways

Seal porosity, cracks and joints and give a smooth surface. Concrete must be cured, clean and dry.

Steel

Steel tanks

Blast and prime, then line to stop corrosion. See tank lining.

Fiberglass

Fiberglass tanks

Sand and prime to bond to old gelcoat and seal blisters and cracks.

Ponds

Earthen ponds

Polyurea over geotextile builds a seamless liner. See polyurea liner.

Display

Aquariums and exhibits

Public aquariums and zoos often set stricter specs; get them in writing first.

Systems

Sumps and filters

Filter boxes, sumps and channels in recirculating systems.

Compare

Aquaculture lining options compared

OptionStrengthsWatch-outs
Spray polyureaSeamless, thick, flexible; cures in secondsNeeds plural-component equipment and trained applicator
EpoxyHard, smooth, good adhesionRigid; cracks with concrete movement; longer cure
Sheet liner (PVC, EPDM, HDPE)Lower material cost for simple shapesSeams, punctures, folds on complex shapes
Cementitious coatingFamiliar for concretePorous; less leak and chemical resistance
Typical comparison. Confirm suitability for aquatic service with the product maker.
Color and lightMany facilities choose tank colors for fish behavior and visibility. Ask what colors the lining comes in before you order.
Do it right

Lining a fish tank

  1. Drain and clean

    Remove fish, water, biofilm and loose material.

  2. Prepare

    Blast or grind concrete and steel; sand fiberglass. Repair cracks and spalls.

  3. Dry and prime

    Let the surface dry to the primer limits, then prime.

  4. Spray the lining

    Spray to the specified thickness and detail pipes, drains and penetrations.

  5. Cure fully

    Hold the cure time at the right temperature before any water contact.

  6. Fill, flush and test

    Fill, circulate, drain and refill, then test water before stocking.

Where we fit

Why polyurea for aquaculture

  • Seamless: no joints to leak or harbor growth.
  • Fast: cures in seconds so tanks return to service sooner.
  • Flexible: bridges shrinkage cracks in concrete tanks.
  • Tough: resists cleaning tools, nets and abrasion.

ArmorThane manufactures pure polyurea for potable and aquatic service and trains the applicators who install it. See AquaShield, water tank coating and koi pond liner.

Aquaculture linings

Seal the tank, protect the stock.

A certified ArmorThane applicator can inspect your tanks, raceways or ponds and quote a fish-safe lining with cure and flush steps spelled out.

Get a free quoteFind an applicator

Contractors: become an ArmorThane applicator

FAQ

Aquaculture tank coating questions

What coating is safe for fish tanks?

Use a product the manufacturer documents for aquatic or potable service, often certified to NSF/ANSI/CAN 61, fully cured and flushed before stocking.

Is polyurea safe for fish?

Pure polyurea products made for potable or aquatic service are used in fish tanks and ponds once fully cured. Follow the product data sheet and flush before stocking.

How long before I can add fish after coating?

Follow the full cure time on the data sheet, then fill, circulate, drain and refill, and test water quality before stocking.

Can you coat a concrete fish raceway?

Yes. Clean, repair and dry the concrete, prime it, and spray a seamless lining to seal cracks and joints.

Can old fiberglass fish tanks be relined?

Yes, after sanding, repairing blisters and cracks, and priming for adhesion.

AT
Written by the ArmorThane technical team. We have manufactured polyurea, polyurethane and polyaspartic coatings, spray foam and plural-component spray equipment in Springfield, Missouri since 1989. Suitability for aquatic life depends on the product, cure and water conditions; always follow the product data sheet.

Sources

  1. NSF, NSF/ANSI/CAN 61 drinking water system components. nsf.org/knowledge-library/nsf-ansi-standard-61-drinking-water-system-components-health-effects
  2. NOAA Fisheries, aquaculture overview. fisheries.noaa.gov/topic/aquaculture
  3. ArmorThane aquatic coatings article. armorthane.com/aquatic-coatings

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