Diodon holocanthus: an Endearing Puffer for Spacious Aquariums

Porcupine pufferfish (Diodon holocanthus)

Porcupine pufferfish (Diodon holocanthus)

Circumtropical in distribution and ascribed more common names than one can possibly keep straight (spiny puffer, porcupine puffer, porcupinefish, longspined porcupinefish, and balloon porcupinefish, to list but a few), Diodon holocanthus can be a worthy, very pet-like aquarium candidate. This species does, however, have certain non-negotiable needs to be met if it is to live a long, healthy life in captivity.

Physical traits

D. holocanthus has a robust, vaguely (American-style) football-shaped body with prominent, bulbous eyes and numerous elongated spines covering its body. These spines normally lie flat against the fish, but when threatened or harassed, it can swallow water or air, causing its body to inflate to nearly twice its size and its spines to stand erect (thus resembling what everyone else in the world calls a football with spikes all over it). The teeth are fused together to form a beak-like structure. Not the most colorful fish in the sea, D. holocanthus typically has a creamy to light-brown base color with dark-brown mottling and spots. Maximum size is upwards of 2 feet.


Overhead view of the porcupinefish showing it's dark-brown mottling and spots

Overhead view of the porcupinefish showing it’s dark-brown mottling and spots

This is where we get to the first of those non-negotiable care requirements. This puffer’s beak-like teeth are designed for crushing hard-shelled prey, and they grow continuously. If not worn down by hard food items, they will grow to the point that the puffer can no longer eat. So, it’s imperative to offer in-the-shell meaty foods—shrimp, clams, mussels, crabs, etc.—on a routine basis. Otherwise, you’ll eventually have to perform a little amateur dentistry on your puffer to keep them trimmed.

Also note that this species will constantly “beg” for food in almost puppy-like fashion. This doesn’t necessarily mean the specimen is genuinely hungry. It has simply learned to associate your presence with the arrival of food. Don’t be duped into overfeeding!


Another non-negotiable requirement for this species, in my opinion, is a very large tank. I’ve seen recommendations for minimum housing as low as 75 gallons, but this just doesn’t make sense to me. D. holocanthus may be a relatively slow swimmer, but it still gets very large, is a messy eater, and produces a lot of waste. I would put minimum housing for this fish closer to twice that recommended size—at least around 150 gallons.

A larger tank will also allow for some creative aquascaping to provide this fish, which tends toward the nocturnal, lots of places (ledges, caves) to hide as well as open swimming space.

The iconic football with spikes all over it

The iconic “football with spikes all over it”


Yet another non-negotiable requirement for D. holocanthus is to choose its tankmates with considerable discretion. Slower moving and/or long-finned species may be subject to nipping, and small fish may get eaten. So any piscine tankmates must be big relatively big and boisterous, such as larger angels, tangs, triggers, and wrasses. In some ways, D. holocanthus is better suited to be the star of a single specimen tank.

This puffer is definitely not a good candidate for reef systems, as it is likely to “sample” sessile invertebrates, will consume crustaceans and mollusks, and can really wreak havoc on water quality through its diet and waste production.


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About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. I have had so many of these it is mind boggling. I love this fish and they are fairly common on the reefs. As was said, they get very big and besides eating hard shelled inverts, they will also bite you and take a piece of your finger with them. They also do not like to be in captivity and spend large portions of their day swimming up and down a pane of glass trying to get through it. When they do this, they keep rubbing their beautiful eyes on the glass so they are ripe for eye infections. They also commonly go blind in a reef tank probably because on a reef they rest under rocks or at least stick their head under something to “think”. Their blindness can easily be cured by feeding meaty foods such as earthworms, one of their favorite foods and keeping them in a dimly lit aquarium. If for some reason, they stop eating as they sometimes do. You can remove them from the water and before they inflate, stick food in their mouth with a toothpick and quickly put them back in the water. They don’t know how to puke so they swallow the food if you stick it far enough into their mouth. Don’t let them inflate especially if you have them in a nano which would just be silly anyway.
    When they get to large I donate them to a public aquarium. What ever you do, don’t let them see those dried, inflated puffers that some Jibonis hang in their house and put a light bulb in it. I hate that and so do they.

  2. Les Melling says

    I would echo much of what Paul says above and the Dog Faced puffer which I have kept is very similar in its requirements and traits. Should a specimen contact an eye infection I have found the addition of iodine in the tank water helps and in severe cases even painting iodine directly onto the eye often affects a cure but I would only do this should the eye not clear either through foods or the addition of iodine to the aquarium.

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