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Pea Puffers: Frequently Asked Questions

Updated: 3 days ago

Pea pufferfish are among the most misunderstood fish in the aquarium hobby. Their small size, expressive behaviour, and wide availability have made them enormously popular, but that popularity has been matched by a persistent spread of poor, outdated, and often contradictory advice. As a result, many pea puffers are kept in inappropriate conditions, not through neglect, but through misinformation presented as fact.


This FAQ continues our Pea Puffer Series, expanding on the foundations laid out in the original Care Guide and addressing the problem of misinformation directly.

Are pea pufferfish freshwater or brackish?


Pea pufferfish are a true freshwater species.


While the majority of pufferfish are found in marine or brackish coastal environments, a smaller group has evolved to live entirely in freshwater.

These freshwater puffers occur across Africa and Asia, inhabiting rivers, floodplains, and lakes, and they show no biological requirement for salt at any stage of their life cycle.


The pea pufferfish, Carinotetraodon travancoricus, belongs firmly within this freshwater group.


The idea that pea puffers require brackish conditions is a persistent myth, often repeated because puffers as a group are commonly associated with marine or estuarine habitats.


This generalisation is incorrect. Freshwater pufferfish are not marine fish kept artificially in freshwater. They are a distinct and highly diverse group that has adapted fully to inland environments.

Are pea puffers endangered?


Pea pufferfish are listed as Vulnerable on the IUCN Red List. They are not formally classed as Endangered, but they are considered a threatened species, with wild populations in decline.


The species is native to a relatively small area of southern India. Many of the shallow freshwater habitats it relies on have been heavily altered or lost due to agriculture, pollution, and water management. Because pea puffers do not have a wide natural range, local damage can have a disproportionate impact on overall population numbers.


Collection for the aquarium trade has also played a role. Pea puffers became popular quickly, and for many years large numbers were exported from the wild. Captive breeding now exists, but wild-caught fish are still present in the trade, and it is not always obvious which is which at the point of sale.


They are also not especially fast breeders. Compared to many small aquarium fish, their reproductive output is low, which limits how quickly depleted populations can recover.


This does not mean pea puffers should not be kept in aquaria. It does mean they should be sourced carefully, kept properly, and treated as animals with a real conservation context, not disposable novelty fish.

Are pea pufferfish a shoaling fish?


Yes. Pea puffers are a shoaling species, just not in the neat, textbook sense people usually imagine.

They do not move as a tight, synchronised group, and they are not constantly swimming together in open water. In the wild, pea puffers occupy the same shallow, plant-choked environments and move through them in loose, overlapping groups.


Individuals keep their own space, but they are very aware of one another and adjust their behaviour accordingly.


This kind of loose shoaling is common among small freshwater fish that rely on cover rather than speed. It is social behaviour, but it is subtle. You see it in how they position themselves, how they react to movement, and how often they choose to be near, rather than away from, other pea puffers.

The idea that they are solitary comes largely from aquarium setups that do not allow this behaviour to show itself.

Should pea pufferfish be kept in groups?


Yes.

When kept in groups, pea puffers tend to behave more naturally. Aggression is not eliminated, but it is spread out. Fish establish pecking orders, shift territories, and then settle.


In contrast, single fish or very small groups often become tense or overly reactive, even if that is not immediately obvious.


This does not mean group keeping is always easy. Without dense planting, wood, and broken lines of sight, social behaviour quickly turns into constant chasing. That is usually where the advice to keep them alone comes from.


Group setups work because they mirror how the species lives in the wild, not because pea puffers are peaceful fish. They are not. They are social fish with sharp boundaries.

For a more detailed look at how pea puffers interact with one another, including observations from both wild and captive environments, see The Social Life of Pea Puffers.

What is the minimum tank size for pea pufferfish?


A group of six pea puffers should be kept in no less than 60 litres, using a tank with a good horizontal footprint and dense structure.

As numbers increase, space should increase with them.

A practical guideline is around one pea puffer per 10 litres, which allows territories to form and reduces persistent aggression. Smaller tanks leave little room for disengagement and tend to fail gradually rather than obviously.


Larger tanks are always easier to manage and produce more stable social behaviour.


For the full context behind these recommendations, including how space and social dynamics interact in practice, see the Tank Size section of our detailed Pea Puffer Care Sheet on Pufferfish Enthusiasts Worldwide. Read the in‑depth tank size guidance from the original care guide.

What substrate is best for pea pufferfish?


Pea puffers should be kept on fine, smooth sand.


Some individuals will attempt to hide by pushing into the substrate when startled. A soft sand base allows this behaviour without risk of injury. Coarse gravel and sharp substrates increase the chance of damage and offer no benefit to the fish.


In nature, pea puffers live over soft riverbeds mixed with organic debris and leaf litter.


Replicating this with sand supports natural behaviour and creates a more secure environment.


If nutrient-rich plant substrates or aquasoils are used, they should be capped with at least 1.5 cm of fine sand to provide a safe surface layer.


For a broader look at how substrate fits into a successful environment, including plants, hardscape, and flow, see Building the Perfect Pea Puffer Environment on Pufferfish Enthusiasts Worldwide.

What do pea puffers eat?


Pea puffers are micropredators and should be fed small invertebrates.

They naturally hunt moving prey, so live and frozen foods work best.

A varied feeding routine matters more than any single food. Rotating different options supports good condition, confident behaviour, and long-term health.


Suitable options include:


  • Grindal Worms

  • White Worms

  • Blackworms

  • Earthworms Click here to read our article on Earthworms

  • Microworms, Banana Worms, and Walter Worms

  • Ramshorn Snails

  • Bladder and Pond Snails

  • Daphnia and Moina

  • Cyclops and Copepods

  • Seed Shrimp (Ostracods)

  • Juvenile Shrimp

  • Mosquito Larvae

  • Glassworm (Chaoborus larvae)

  • Bloodworms (Chironomid larvae)

  • Springtails

  • Vinegar Eels

  • Aphids


For a deeper look at feeding strategy and food choice, see Pea Puffers: Rethinking Food Variety.

Do pea puffers eat snails?


Yes. Small freshwater snails are a natural and readily accepted food for pea puffers.

In the wild, pea puffers regularly prey on small shelled invertebrates while foraging through plants and debris. In captivity, appropriately sized snails provide both nutrition and behavioural enrichment. They encourage hunting, manipulation, and problem-solving, rather than passive feeding.


Snails should be treated as a supplementary food, not a daily requirement. Unlike larger puffer species, pea puffers do not suffer from rapid tooth overgrowth and do not need constant access to hard-shelled prey. Occasional snail feeding is sufficient when combined with a varied invertebrate diet.


Only small snails should be offered. Ramshorn snails and bladder or pond snails are ideal, as they can be consumed completely. Larger snails are often attacked but not eaten, leaving injured or dead animals hidden in the tank. Decomposing snails can quickly degrade water quality, particularly in smaller aquaria.


As a general rule, if a snail cannot be eaten fully, it should not be offered and any uneaten remains should be removed promptly.

What water parameters do pea pufferfish need?


Pea puffers are adaptable, but they do best in clean, stable, near-neutral freshwater.

A practical target range is:


  • pH: 6.8–7.8 (stable around 7.2–7.5 is ideal)

  • Temperature: 25–28 °C (75–82 °F)

  • Nitrate (NO₃): <15 ppm (aim for as close to zero as you can manage)

  • GH: 7–12 dGH (≈120–200 ppm) is ideal; tolerances from 5–25 dGH have been reported

  • KH: 4–7 dKH, enough to buffer against pH swings

  • TDS: 180–250 ppm when GH/KH are in range

For the full parameter ranges, field context, and explanation behind these targets, see the Water Values section of the original Pea Puffer Care Guide.

How important is nitrate for pea pufferfish?


Nitrate is a silent long-term stressor in closed aquarium systems.

Ammonia and nitrite are acute hazards, but nitrate accumulates and quietly affects fish over time. It is soluble and persistent unless removed by water changes or biological uptake. In nature, flowing rivers rarely allow nitrate to build up, so captive systems must manage it deliberately.


Pea puffers do best with nitrate kept below about 15 ppm, and many experienced keepers aim even lower. Consistently low nitrate correlates with stronger growth, brighter colours, more natural behaviour, and longer lifespans.


For a deeper look at how nitrate affects pea puffers and how to manage it effectively, see Why Nitrate Isn’t Just a Number: The Hidden Danger on Pufferfish Enthusiasts Worldwide.


 
 
 
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