Pea Puffer (Carinotetraodon travancoricus)

Breeding Pea Puffers is moderately difficult but achievable with proper conditioning, a dedicated spawning tank, and meticulous fry rearing. They are substrate spawners that deposit eggs in dense moss.

Pre-Spawning Conditioning (2-3 Weeks)

Separate males and females into different tanks for at least 14 days. Condition both sexes with live blackworms, daphnia, and snails fed 2-3 times daily. Maintain temperature at 78°F - 80°F (25.6°C - 26.7°C) and perform 30% water changes every 3 days.

Spawning Tank Setup

Use a 10-gallon (38 liter) bare-bottom tank with a large air-driven sponge filter. Fill with aged, soft water at pH 6.8-7.2, GH 5-8 dGH, temperature 78°F - 80°F (25.6°C - 26.7°C). Provide two large clumps of Java moss or spawning mops as egg deposition sites. No substrate necessary; bare bottom makes egg spotting and cleaning easier.

Spawning Process

Introduce 1 male and up to 3 females to the spawning tank. The male chases females and leads them to the moss. Spawning typically occurs within 3-7 days of introduction. The female deposits 1 to 5 eggs per day over several days, attaching them to moss filaments. Eggs are tiny, clear to pale yellow, and adhesive.

Remove all adults immediately after spawning is observed. Pea Puffers will consume their own eggs and fry readily.

Incubation and Hatching

Eggs hatch in 4 to 5 days at 78°F (25.6°C). Newly hatched fry rest on the bottom for an additional 5 days, absorbing their yolk sacs. They are extremely small at approximately 0.1 inches (2.5 mm).

Fry Rearing Protocol

• First food (Days 1-5 post-free-swimming): Infusoria (Paramecium) and vinegar eels. Feed continuously
• Second food (Days 5-10): Microworms and newly hatched brine shrimp (Artemia nauplii)
• Third food (Days 10-14): Baby brine shrimp and crushed snails
• Water changes: 20% daily using airline tubing siphon to avoid sucking up fry
• Filtration: Sponge filter only. Never use power filters with fry

Fry grow slowly, reaching 0.5 inches (1.3 cm) in 8-10 weeks. Separate by size to prevent cannibalism.

Tank mate selection for Pea Puffers is extremely limited due to their aggressive fin-nipping behavior, small size, and specialized dietary requirements. Species-only tanks are strongly recommended and represent the only guaranteed safe configuration.

Occasionally Compatible (Monitor Closely)

• Otocinclus catfish (Otocinclus spp.): The most reliable companion. Fast, armored, and occupies a different niche. Pea Puffers generally ignore otos. Requires established algae or supplemental feeding
• Chili Rasbora (Boraras brigittae): May work in heavily planted 20+ gallon tanks with 12+ puffers. Fast schooling behavior helps avoid nipping. Success is never guaranteed
• Celestial Pearl Danio (Danio margaritatus): Similar to chili rasboras; requires dense planting and large tank. Monitor for fin damage daily
• Amano Shrimp (Caridina multidentata): Large enough to avoid predation in most cases. Small shrimp (cherry, ghost) are usually eaten

Absolutely Incompatible

• Any slow-moving or long-finned fish: Betta, guppy, molly, platy, angelfish, gourami, fancy goldfish. Fins will be shredded within hours
• Small peaceful bottom dwellers: Corydoras, small loaches. Puffers nip barbels and fins relentlessly
• Small shrimp: Cherry shrimp, ghost shrimp, bee shrimp. Consumed as food
• Other puffer species: Different size, water parameter needs, and aggression levels create lethal conflicts
• Competitive feeders: Any fish that outcompetes puffers for live or frozen food will starve them

Critical Rule: If you attempt a community setup, the tank must be 20+ gallons (76+ liters) with dense planting and broken sightlines. Keep 12+ puffers so they focus aggression on each other rather than tank mates. Have a backup tank ready for immediate separation at the first sign of fin nipping.

Pea Puffers originate from shallow, slow-moving rivers in India with sandy or silty substrates scattered with leaf litter and submerged wood. Replicating this biotope reduces stress, encourages natural behavior, and enhances their stunning coloration.

Substrate Requirements

Use fine, smooth sand (pool filter sand or aquarium-specific fine gravel 1-2 mm) at a depth of 1 - 2 inches (2.5 - 5 cm). Pea Puffers exhibit a startling escape behavior where they dive headfirst into the substrate when startled. Coarse or sharp gravel causes severe mouth and eye injuries during this instinctive response.

If using nutrient-rich plant substrates or aquasoils, cap with at least 0.5 inches (1.3 cm) of fine sand to create a protective surface. Dark-colored sand (black or dark brown) enhances their gold and green iridescence and reduces skittishness.

Hardscape and Planting

Provide more hiding spots than puffers. Essential elements include:

• Java moss (Taxiphyllum barbieri): Critical for egg laying, fry rearing, and general security. Use large clumps
• Driftwood: Red moor wood, Mopani, or small driftwood pieces create caves and visual barriers
• Rockwork: Smooth river pebbles or small lava rocks. Avoid sharp edges
• Stem plants: Limnophila sessiliflora, Cryptocoryne, and Amazon Sword provide mid-ground cover
• Floating plants: Amazon Frogbit, Water Lettuce, or Duckweed filter light, soften reflections, and recreate the dappled shade of their native habitat

Water flow must be gentle to moderate. Pea Puffers are weak swimmers; strong currents exhaust them and prevent normal foraging behavior. Use sponge filters or adjust canister filter outputs with spray bars or baffles.

Accurate sexing of Pea Puffers is essential for group stocking. Incorrect ratios lead to relentless male harassment, female death, and chronic tank warfare.

Sexual Dimorphism

• Males: Smaller and more slender body shape. Develop a dark line or wrinkle down the center of the belly when sexually mature (4-6 months old). Often display iridescent wrinkles or creases on the face, particularly around the eyes. More aggressive and territorial
• Females: Larger and distinctly rounder, plumper body shape, especially when gravid with eggs. Lack the dark belly line. Generally more mellow but will defend territory when necessary

Why Sexing Matters

Maintain a ratio of 1 male to 2 or 3 females minimum. All-male groups result in constant warfare. Groups with excess males experience persistent chasing, fin nipping, and stress-induced illness in females. In a 6-puffer group, aim for 2 males and 4 females. In a 10-puffer group, 3 males and 7 females is ideal.

When buying from a store, hand-select each individual rather than accepting a random bag. Look for plump, rounded females with bright eyes and active behavior. Avoid thin, lethargic individuals with hollow bellies, as these often carry heavy parasite loads from wild collection.