Fish Breeding Supplies

The core supplies for breeding fish are a dedicated breeding or fry tank (10-20 gallons typically), a sponge filter, a reliable heater, a spawning medium appropriate to your species (moss, slate, spawning mop, or cave), and a way to raise fry food (infusoria, baby brine shrimp, or microworms). Beyond that, the specifics depend entirely on which fish you're breeding, since the needs of egg scatterers like danios are completely different from mouthbrooders like cichlids or bubble nesters like bettas.

This guide covers the essential supplies for breeding common aquarium fish, how to set up a functional breeding operation on a budget, species-specific considerations, fry-raising equipment, and the supplies that experienced breeders consider non-negotiable vs. Optional.

The Breeding Tank Setup

Tank Size and Configuration

A 10-gallon tank is sufficient for breeding small fish like guppies, bettas, corydoras, and many tetras. A 20-gallon long provides more room for larger fish or pair-bonding cichlids that need space to court without feeling crowded.

For a basic fry-raising setup after the spawn: - Small species (guppy, endler, neon tetra): 5-10 gallon grow-out tanks work - Medium species (angelfish, discus, severum): 20-30 gallon grow-out - Large species (oscar, large cichlids): 40+ gallons for grow-out

The breeding tank is typically kept bare-bottom or with minimal substrate, making it easier to spot eggs, siphon waste, and monitor fry. Bare-bottom also prevents eggs from falling into substrate where fungus can attack them.

Sponge Filters: The Non-Negotiable Fry Tank Filter

Standard HOB (hang-on-back) and canister filters are dangerous in fry tanks. The intake can suck up newly hatched fry or even eggs. A sponge filter is the standard choice for breeding and fry-raising tanks for several reasons:

• The sponge pore size is small enough to prevent fry ingestion
• Sponge filters house beneficial bacteria for biological filtration
• They create gentle water movement rather than strong currents
• They're inexpensive ($3-10 each) and easy to clean

Popular sponge filter brands: Hikari Bio-Pure Sponge Filters, Aquarium Technology Inc. (ATI) sponge filters, and the XY-2835 double sponge filter commonly used in fishrooms. Connect them to a small air pump via airline tubing.

Pre-seeding a sponge filter in your main tank for 2-4 weeks before moving it to a new breeding tank gives it an established bacterial colony, which means no cycling period in the new tank.

Heater

Most tropical breeding fish spawn more readily and have higher fry survival rates at the warm end of their temperature range. Guppies breed best at 78-82°F. Bettas prefer 80°F for breeding. Discus spawn at 86-88°F.

A precise heater matters in a breeding tank. The Cobalt Aquatics Neotherm maintains temperature within 1°F, which reduces temperature stress on eggs and new fry. For very small breeding tanks (5 gallons), the Eheim Jager 25W or Aqueon Pro 50W are appropriate wattages.

Spawning Equipment by Fish Type

Egg Scatterers (Danios, Tetras, Barbs, Rasboras)

These fish scatter eggs randomly, and the parents will eat them if given the opportunity. The solution is a spawning grate or a thick layer of spawning mops that eggs fall through, putting them out of reach of the adults.

Spawning grates: Plastic grids placed 1-2 inches above the tank bottom. Eggs fall through the holes, parents can't reach them. Work well for danios, zebra danios, and white clouds.

Yarn spawning mops: Bundles of green acrylic yarn tied in a bunch and floated or sunk in the breeding tank. Eggs attach to the yarn fibers. Remove the adults after spawning, or move the mop to a separate hatching tank. Cheap to make yourself ($2-5 in yarn from a craft store).

Java moss and fine-leaved plants: Provide a natural spawning surface for fish like cardinal tetras and some rasboras. Eggs hide among the moss strands.

Egg Depositors (Corydoras, Angelfish, Discus)

These fish choose a specific surface to deposit eggs on: broad leaves, flat rocks, the aquarium glass, or cave entrances. They tend the eggs rather than eating them.

Spawning slates and smooth rocks: Flat pieces of slate or smooth river rocks give surface spawners like corydoras a preferred substrate. Position them at a 45-degree angle to mimic how corydoras naturally spawn on plant leaves.

Broad-leaved plants: Amazon swords and anubias provide natural spawning surfaces for angelfish and discus. Live plants, if you're comfortable with them, or plastic replicas work nearly as well for the spawning surface itself.

PVC caves: For cave-spawning species like German blue rams, cockatoo cichlids, and bristlenose plecos, 1.5-2" diameter PVC pipe cut to 4-6" lengths make ideal spawning caves. Inexpensive (under $5 for a 10-foot section of PVC from a hardware store) and easy to monitor egg development.

Bubble Nesters (Betta, Gourami, Paradise Fish)

Male bubble nesters build foam nests at the water surface and place eggs inside the bubbles after spawning. The male guards the nest.

Floating plants: Indian flocculant moss (Salvinia), water lettuce, or small-leaved floating plants give the male anchor points for the bubble nest and reduce surface agitation that would destroy it.

Low water level: Breeding bettas typically need a water depth of 5-8 inches, not a full tank. Lower water makes it easier for the male to retrieve eggs and maintain the nest.

Dividers: Used to separate male and female bettas during the conditioning period before introducing them for breeding.

Mouthbrooders (Many Cichlid Species, Some Killifish)

Mouthbrooders carry fertilized eggs in their mouth until the fry are free-swimming. The main supply consideration is caves or flat rocks for spawning initiation and a tank large enough that the brooding female (or male, depending on species) can retreat from aggressive tank mates.

For mouthbrooding cichlids like Aulonocara (peacocks) and Mbuna, a holding tank (10-20 gallons) where you can strip the mother and artificially tumble the eggs is used by serious breeders. An egg tumbler (a small mesh cone suspended in an airstream that keeps eggs rolling) replaces the mother's mouth movements and prevents fungusing eggs.

See our Best Aquarium Equipment guide for filtration and heater comparisons.

Raising Fry: The Food Problem

Most aquarium fish fry are too small to eat flake food for the first 1-3 weeks of life. The fry food options from smallest to largest:

Infusoria

Infusoria is a culture of microscopic organisms (paramecia, rotifers, small protozoa) that first-feeding fry can eat immediately after hatching. You make infusoria by adding a small amount of plant material (lettuce, spinach, hay) to a jar of water and letting it sit in indirect sunlight for 3-5 days. The cloudy water is fed to fry by the teaspoon.

Works best for: very small fry like tetras, bettas, and corydoras in the first week.

Baby Brine Shrimp (BBS)

Hatching baby brine shrimp from eggs is the standard fry food for most aquarium fish once they're 5-7 days old. Brine shrimp eggs (cysts) are purchased dry, hatched in saltwater in 24-48 hours, and fed live to fry.

Equipment needed: - Brine shrimp hatchery: A plastic or glass cone-shaped container with an airstone at the bottom. DIY versions use 2-liter bottles inverted. Commercial versions (San Francisco Bay Brand Hatchery Kit, Ziss Bubble Bio Filter as hatchery) are more convenient. - Brine shrimp eggs: San Francisco Bay Brand, Brine Shrimp Direct, and Ocean Star International are reliable brands. Store in the refrigerator in a sealed container. - Aquarium salt or marine salt: For the hatching saltwater solution (1 tablespoon per quart). - Harvest equipment: A fine mesh brine shrimp net to separate hatched nauplii from shells.

BBS are nutritionally rich and eagerly accepted by most fry. The hatching routine of starting a new batch every 24 hours ensures a constant supply.

Microworms, Vinegar Eels, and Walter Worms

Live worm cultures are another live food option for small fry. Microworms (Panagrellus redivivus) are grown in a container of oatmeal or cornmeal and harvested by collecting the worms from the container walls. They're approximately the same size as BBS nauplii and provide good nutrition.

Starter cultures are available from other hobbyists, fishkeeping groups, and some online suppliers. Once established, a culture lasts months with weekly feeding.

Powdered Fry Foods

Hikari First Bites, Sera Micron, and Omega One Fry Food are powdered commercial options that work for supplementing live foods once fry are a week old. They're convenient but less eagerly accepted by many species than live foods, and water quality degrades faster with powder than with live foods.

Water Quality Management for Fry

Fry are more sensitive to ammonia than adult fish. In a new breeding tank without a cycled sponge filter, even small amounts of uneaten food can spike ammonia to dangerous levels.

Daily small water changes of 5-10% using water matched to tank temperature and dechlorinated with Seachem Prime are the standard practice during active fry-raising. Use a small turkey baster or air line tubing as a siphon to remove waste from the tank bottom without sucking up fry.

Our Top Aquarium Equipment roundup covers testing kits for monitoring ammonia and nitrite during fry-raising.

FAQ

What's the easiest fish to breed for beginners? Guppies, endlers, and mollies (livebearers) are the easiest because the female gives birth to fully formed fry that can eat crushed flake food immediately. No eggs to worry about, no infusoria phase, and the fry grow quickly. Corydoras catfish are the next step up and are excellent for learning egg-depositor breeding.

Do you need a separate tank to breed fish, or can they breed in the community tank? Community tank breeding works for livebearers if you add a breeding box or dense plants for fry to hide in. For egg layers, a separate breeding tank is strongly recommended because most adult fish eat eggs given the opportunity, and monitoring egg development is much easier in a dedicated setup.

How long does it take for aquarium fry to reach sellable size? This varies enormously by species. Guppy fry take 3-4 months to reach sexual maturity. Angelfish fry take 6-12 months to reach 2 inches. Discus take 8-12 months. Corydoras reach 1 inch (typical sellable size for local fish stores) in about 4-6 months.

What should I do with the fry once they're grown? Local fish stores often take locally bred fish as store credit, especially for popular species like corydoras, guppies, and angelfish. Aquarium clubs often have buy/sell/trade forums. Local hobbyist Facebook groups and Craigslist are other options. Resist the urge to release fish into local waterways, as this is illegal and ecologically damaging in most areas.

Building Your Breeding Supply Kit

Start simple: a 10-gallon tank, a pre-seeded sponge filter, a reliable heater, an air pump and tubing, and a brine shrimp hatchery setup. For egg scatterers, add a spawning mop. For surface spawners, add slate or PVC caves. For bubble nesters, add floating plants. Total cost for a functional first breeding setup runs $50-100, not counting the fish. Complexity can grow from there as you gain experience with specific species.