Updated: Nov 9, 2020

This care sheet is written with the aim of providing the optimal care for this species of fish.

Pufferfish Enthusiasts Worldwide endeavours to inspire and promote the highest standards of care - not basic or minimum care - using the best evidence available at the time.


The main priority at Pufferfish Enthusiasts Worldwide will always be to provide the most accurate and up to date information pertaining to individual species and their care. Although we do greatly encourage the use of binomial names (scientific names) because common names can be so misleading for pufferfish, we sometimes have to make concessions for SEO reasons. We realise that most people are not going to search "Carinotetraodon travancoricus care" and are instead more likely to search for "pea puffer care", so this care sheet is going to refer to them by their most frequently used common name, so that new and prospective owners will be able to find this information through a Google search.

Introduction

The travancoricus is a species of freshwater pufferfish, from the Carinotetraodon genus, which is endemic to Kerala (was Travancore), Southwestern India.


It is famous for its maximum known size of less than 25mm (0.98 inches), making it the smallest known species of pufferfish in the world.


This small size has earned this species several common names which include, pea puffer, pygmy puffer and dwarf puffer. For this care sheet, we are going to refer to them using their most frequently used common name, the Pea Puffer. Despite this species being the most common pufferfish in captivity, the internet is still plagued with erroneous information, with most care guides completely failing to recognise that this species is in fact a shoaling fish, recommending unsuitable foods which may be very unhealthy for the fish over the long term and tanks that are too small. Unfortunately, the more common a species is, the more folklore seems to surround them. Pufferfish Enthusiasts Worldwide intends to set the record on this species straight.

The Carinotetraodon imitator


There is another species which closely resembles the C.travancoricus, that is frequently misidentified as being the same fish. The other species is appropriately called the Carinotetraodon imitator. The same husbandry laid out in this guide can also be applied to C.imitator.


More details on identification coming soon.

In the wild

The pea puffer is known to inhabit 13 different rivers, in addition to several estuaries, across Kerala and southern Karnataka in the Western Ghats of Peninsular India.


Unlike most other species of freshwater pufferfish, with a couple of exceptions, the pea puffer is naturally found in large shoals of their own kind, for social and security reasons.


The beds of the rivers and streams which these fish inhabit are covered with leaf litter from the overhanging vegetation. This provides the perfect habitat for the copepods, water fleas, insects and their larvae which these pufferfish prey upon. The presence of sand and detritus within the stomachs of wild-caught pea puffers, in a study conducted by the University of Kerala (Laboratory of Conservation Biology, Department of Zoology) indicates that this species is a frequent bottom feeder.


The pea puffer (Carinotetraodon travancoricus) is classified as ‘vulnerable’ on the IUCN Red List due to habitat loss, pollution and over-fishing to supply the aquarium trade. It remains relatively common in some areas of India but it is becoming increasingly rarer in other areas where it is believed that the population has decreased by as much as 50%.

In the aquarium

The pea puffer is by far the most commonly kept species of pufferfish, owing to their full grown size of just 2.5cm (0.98 inches). Pea puffers are very popular among beginner keepers and demand for them has only continued to grow. Imports of wild-caught pea puffers are very common, but the species is frequently bred in both home aquaria and commercial breeding facilities, which is reassuring considering that their wild numbers are in decline.

The pea puffer best thrives in heavily planted tanks which offer them plenty of areas to hide and lots of visual barriers to break up open spaces. Such a scape helps this species feel safe, knowing that they can take cover quickly if they need to.

A huge variety of different aquascaping styles can be used in a pea puffer tank and the possibilities are almost endless.


Driftwood, red-moor, mopani wood, rounded boulders, Dragon stone and lava rock are just a few examples of materials that can be used in your pea puffer aquarium. Amazon swords, Java fern, crypts, Anubias and stem plants, such as Limnophila sessiliflora, are all very good plants options. Floating plants, such as Amazon Frogbit, give dappled shade which is also appreciated by this fish.


Pea puffers cherish various different types of mosses, such as Java moss (Taxiphyllum barbieri), Weeping Moss (Vesicularia Ferriei), Christmas moss (Vesicularia montagnei) and will hide and sleep in the soft vegetation. An abundance of moss is actually the secret to pea puffer breeding as they use it as a spawning medium and it offers the fry harbourage.


The flow in the aquarium should be slow to medium and never overpowering.

The pea puffer is not a strong swimmer, so a powerful current is not suitable.

Although these pufferfish are very adaptable, they are intolerant of poor water conditions so a mature tank, decent filtration and frequent water changes are essential. We recommend a minimum water change schedule of 50% every seven days.


Not many people realise how long these little fish can live with the proper care, with the general consensus being that they live for around 3 years. In actual fact, is not unusual for well cared for pea puffers to live for over 6 years, with some known to live to the grand old age of 12 years old.

Substrate


Little known fact, this species (like other members of Carinotetraodon) will bury itself in the substrate when scared. They can nose-dive the bottom of the aquarium when they feel that they are at risk of predation and disappear into the substrate like a bullet. We have seen pea puffers become injured when they attempt to do this on substrates that are too hard. This is why the substrate must be a fine, soft sand to avoid injury to the fish. Aquasoils and plant substrates can be used, but it must be capped with at least 1.5cm of fine sand.

Group size

Unlike most other species of freshwater puffer (with a couple of exceptions), the pea puffer is naturally found within shoals, for social and security reasons. It may be easy to think of the pea puffer as an unassailable little predator in the wild, with no fear of other fish, but this is far from the truth.

The small size of the pea puffers makes them very vulnerable to predation and there are many fish who consider it a fun-size snack. Contrary to popular belief, the toxin that the pea puffer contains does not grant it immunity from all predators.

This is why they shoal. Being a part of a large group gives them enhanced predator detection, with more eyes looking around, which reduces the chances of individual capture.


Subsequently, shoaling brings with it a sense of security and is why this species becomes very nervous and shy when kept either alone, or in groups that are too small.


They should never be kept alone or in groups consisting of less than 6 individuals.

When kept in groups of at least six, they are much more confident, have a better feeding response, are more social and less aggressive to each other.


When pea puffers are stressed, they can become very aggressive which leads to fighting within the group. This is why small groups experience more infighting. This same behaviour can be observed in other species of shoaling fish which are housed incorrectly.

Male to female ratio

Male pea puffers are more aggressive and territorial than females, which is why it is important to have as few males in the shoal as possible. These fish are just as individualist as their larger relatives, so there is no guaranteed ratio, but it is recommended to keep at least two females to every male.

Example, a group of 6 would contain 4 females and 2 males.

Tank size

As this species is a shoaling fish, the minimum tank size should be at least 60L (15.85 US gallons) for the minimum group size of 6. One pea puffer per 10 litres (2.64 US Gallons) of tank water is a good stocking density for this species. This recommendation is based on the fish's behaviour and water quality test results when kept this way. For example, a 60 litre tank (15.85 US Gallons) can comfortably house the minimum group size of six, long-term. 60L = 6 pea puffers

80L = 8 pea puffers

100L = 10 pea puffers

120L = 12 pea puffers

The "5 and then 3 gallon" recommendation


There is an old suggested tank size of 5 US gallons (18.93 litres) for a single pea puffer and then 3 US gallons (11.36 litres) for every additional puffer. This recommendation seems to have been plucked from thin air and is not based on any solid reasoning. This suggestion also completely ignores the fact that this species is a shoaling species and should never be housed alone.

Water values


Maintain the following water parameters:

  • PH: 6.5 - 7.5 (in the middle is ideal)

  • Temp: 22 - 27.5c

  • N03: below 15ppm (as close to zero as possible)

  • NH3/NH4+: 0ppm

  • N02: 0ppm

  • GH: 5-25 dGH

Tankmates

The pea puffer is almost as famous for nipping the fins of other fish as it is for being small and it is for this reason we strongly recommend a species only aquarium. However, when the pea puffer is kept in large shoals (with over 20 members) and large tanks they become much less interactive with other fish because they are so occupied with themselves. When they are kept in large shoals, they can be housed with some other fish, but this is not completely without risk and the keeper should be prepared to monitor the behaviour and separate the other fish if theres any evidence of fin nipping or harassment.


Any potential tank mate must be peaceful, fast-swimming, short-finned, and able to thrive in the same water parameters. This rules out fish such as guppies, angelfish, gourami and Betta. Ideally, any tank mate would be from one of the same regions as the pea puffer to.

The pea puffer should not be housed with any bottom-dwelling fish, such as corydoras, who may encroach on their hiding spaces within the scape, or any fish who may over-compete with the pea puffer for food.


Dawkinsia rohani can make good tank mates, but be mindful that your tank should also be big enough to support a group, because these are also a shoaling fish.

Providing that the water values are suitable and that the aquarium is both large enough and mature enough to support a group, the smaller species of catfish from the Otocinclus genus may be used in the C.travancoricus tank for minor algae control.


Some keepers report a harmonious relationship between their pea puffer and small shrimp such as the Red Cherry (Neocaridina davidi) and Amano (Caridina multidentata). Others report bloodbaths, in which the shrimp are slaughtered.

Sexual dimorphism

Juvenile C.travancoricus are very difficult to accurately sex, but become more sexually dimorphic as they age. Mature males have an obvious dark line that runs length-ways over the ventral surface (underside), which the females lack.


Typically, mature males have a pattern of closely-arranged lines around the eye, which are frequently referred to as ‘wrinkles’. Sexually mature females are also rounder in the body than the males.

Buying your pea puffers

We definitely recommend visiting the store to hand select the individuals for your shoal, rather than buying them online without seeing the quality of the livestock first.


It is not uncommon for pea puffers to be sold in a malnourished state and the inexperienced keeper may struggle to completely recover the puffer's health in good time.


Select pea puffers who look bright, active and alert, with no signs of malnourishment or illness. They should obviously be well fed and their bodies should be round and plump.


Like we said, this species is classified as 'vulnerable' by the IUCN because their wild numbers are declining. Now, although the aquarium trade is not entirely to blame, with the threats to this fish also coming in the shape of pollution and habitat loss, we should encourage buying only captive bred examples, so do not be shy to ask your retailer where the livestock has been sourced from and avoid buying wild caught.

Introducing new members to an existing shoal


It is best to buy every member of your shoal from the same place, at the same time, which will ensure that all of your pea puffers settle into the aquarium simultaneously.


If you are introducing new pea puffers into an existing group then firstly make sure the new members are of roughly the same size as your other members and rescape the tank before introducing the new members, to breakup established territories within the tank.

Treating for parasites

Internal parasites (endoparasites) are the only thing that we recommend treating for prophylactically. We recommend treating for worms, even if the pufferfish are captive bred, appear to be healthy, or showing no signs of having parasites. We encourage this because endoparasites can sometimes go unnoticed for a very long time and they are capable of causing serious problems.


We recommend a Levamisole HCI based medication, such as eSHa NDX. Levamisole HCI is effective against Stomach worms, Nodular worms, Hookworms and Lungworms. It is especially effective against Nematodes (roundworms), such as Capillaria, Eustronggylides, Camallanus, and Contracaecum.


Levamisole HCI is not the medication of choice for against Cestodes (tapeworms), and this is where a praziquantel based medication (such as PraziPro) should be used.

Some small crustaceans can act as intermediate hosts for some parasites, so depending on what you feed to the pufferfish and where you source the food from, you may have to worm the fish on a regular basis. We have a guide for parasites coming soon, which we will publish and leave a link for here when it is completed.

Notable behaviour


They have been known to jump out of the water when being pursued by one another, so they must only be housed in an aquarium with a tight-fitting lid.


They are very intelligent and will beg their owners for food once they have made the association.


The pea puffer may occasionally circle other pea puffers with their tail curved. This is a normal sign of defence and short-lived spats are quite common. This behaviour can also be observed when the fish is investigating an unfamiliar object.

Feeding

The pea puffer will rarely take to flake food or pellets or show any interest in freeze-dried foods and because of this, it is important to ensure that the pea puffer received a varied diet of the correct foods. Live and frozen foods are usually excitedly devoured.

Our preferred foods for these fish include:

  • Pinhead crickets

  • Aphids

  • Glassworm (phantom midge larvae)

  • Grindal worm

  • Daphnia/water flea (live or frozen)

  • Brineshrimp/artemia (live or frozen)

  • Small snails - read below

  • Small earthworm (wisps)

  • Blackworm

  • Whiteworm

  • Copepod

  • Mini bloodworm (live or frozen)

This species should not be offered krill, cockle, mussel, clams, oysters or similar mollusks.


Not any one food should make up more than 20% of the fishes overall diet, with bloodworms (read below) not exceeding 10%.

It is best to alternate between different foods on a daily basis and feed several small meals throughout the day rather than offering larger, less frequent meals. This helps with ensuring that the fish are receiving a varied diet, but also to keep the pufferfish occupied.

Bloodworm


Some Facebook groups and care sheets would have you believe that bloodworms alone are a suitable diet. This is actually a very poor diet and is one of the main reasons we don't see pea puffers usually living for as long as they should, like we mentioned above.


There have been reports of pea puffers choking on normal-sized bloodworms, so we recommend mini-bloodworms to prevent this.

Feeding snails and hard-shelled foods

Pea puffers will eat small snails, such as young Segmentina nitida (ramshorn snails) and Physella acuta (Bladder snail), but they do not need to be fed these snails on a very regular basis.

The beak of this species does not grow as rapidly as some others, so the need to feed hard-shelled foods is reduced.

Filtration and tank maintenance

This pufferfish is intolerant of poor water conditions, so a high level of biological and mechanical filtration is needed to deal with the amount of waste that this fish produces.


Good filtration combined with excellent husbandry is essential to the health of this species.

Frequent water changes must be carried out to maintain NO3 (nitrate) levels below 15ppm; or as close to zero as possible.


We recommend a minimum water change of 50% every seven days and extra attention should be afforded to ensure that the base of the dense scape is free from detritus.

Inflation

The pea puffer can inflate themselves when frightened or stressed.

They should never be provoked into inflating!


If the fish needs to be moved for whatever reason, it should be herded into a watertight container under the surface of the water to prevent it from inhaling air.

Disclaimer


Pufferfish health information given on this site is not intended to act as or replace the advice of a certified veterinary professional. If your pufferfish is experiencing a medical emergency, contact an experienced aquatic veterinarian immediately.

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