III. The Figure Eight Puffer; Colorful, Comical, Compact Fish

I have found the Figure 8 puffer (Tetraodon biocellatus), to be the perfect puffer for beginner brackish puffer keepers. It is one of the most colorful of the puffer species, keeping their beautiful markings into adulthood. It is friendly, personable and entertaining. It even stays small enough to keep a singleton in a 15 gallon tank. But remember, larger is always better — these fish like to swim! I recommend 10 gallons for every one extra you may want to add. Also, a longer footprint will give them more swimming room than a tall tank. Singletons have been proven to live longest and seem to have a better relationship with their keepers. Most will get along with cospecifics and other smaller brackish water tank mates, like gobies and small species of mollies (Be wary of larger mollies — I’ve seen Figure 8’s bullied by Sailfin mollies). If keeping multiple F8s together, it would be best to start them out together as juveniles and let them grow up together, as older puffers may not tolerate the addition of new puffer tank mates.

Figure 8 Tank Parameters

Puffers are warm-water, tropical fish, so a temperature of around 78 degrees Fahrenheit is best for them. A substrate of crushed coral or aragonite sand is recommended to keep the pH at a steady level of around 8. Puffers have no scales or gill covers and as a result are extremely sensitive to the toxins present in a cycling tank. As is recommended with all fish, the puffer must be placed into a fully cycled tank, with NO ammonia or nitrite, and low nitrate (under 20 ppm of NO3-N). Although they are mostly found in freshwater in the wild, years of keeping this fish in captivity have shown that they are best kept in low-end brackish conditions. This equates to a specific gravity (S.G.) of around 1.005-1.008. If kept in freshwater, their immune system is apparently compromised, resulting in disease and early death for a fish that can live into its late teens. The longest-lived documented Figure 8 puffer was over 18 years old! Naturally, it was kept in brackish water.

Most brackish puffers are sold in freshwater at the shops, so it is best to cycle (using a method that does not require fish!) your tank at whatever salinity the puffer is kept at in the store you are purchasing it from (bring your own hydrometer/refractometer to check the S.G.).

After the puffer is comfortable in your tank, you can raise the salinity slowly (corresponding to an increase in S.G. of 0.001 – 0.002 per week), to ensure that you don’t disturb the bio-filter in the tank you just cycled. To achieve brackish conditions, it is important to use marine salt, measured properly with either a hydrometer or refractometer. Be sure to find a hydrometer that starts at 1.000 (freshwater) — as many only cover the saltwater range. SeaTest and Instant Ocean are two suggested brands of hydrometers that start at 1.000, but there are many others to choose from. If you are adding the fish from freshwater to your already-established brackish tank, you can drip-acclimate them, by using an air hose with a knot tied in it, so it drips your tank water slowly into a bucket with the water the fish came in, until the salt levels in the bucket match the level inside your tank. I have found that for low-end brackish water fish, the brand of salt isn’t very important; I go with the cheapest, as long as it is made for marine tanks. Heavy filtration is recommended — it is nearly impossible to have too much. 50% weekly water changes are the best way to keep your puffers healthy and happy.

Decorating Your Figure Eight Tank

Puffers are intelligent, curious creatures that become bored easily. I have read many people complaining about their puffers “pacing” up and down against the glass. The solution is simple: Give them something to explore! Visually complex decorations in the tank, breaking up lines of sight, especially with multiple puffers, will do the trick — plants, caves, rockwork and even plastic tubes, like Habitrails have been used to provide a bit of fun for their Figure 8 puffers! You can also try your hand at some of the available brackish plants. Top of the list are Java fern and Java moss (add latin names in parentheses). Even with the proper décor, you must also take time to observe their behavior, as all puffers are at the minimum, potentially vicious fin-nippers or even murderous killers. Even the most seemingly mild-mannered puffer can kill overnight. Watch for fin-nipping and missing fish and take action immediately if found necessary to separate any of the culprits.


Since puffers’ teeth (a beak formed from two plates) are continuously growing, all of them have the potential to get so long that they inhibit the fish’s ability to open and close their mouth to eat. At this point, the only recourse is hand-trimming by their keeper. Although Figure 8 puffers generally pose less of a problem in this respect than other puffers, it is important that they have a constant supply of crunchy, healthy, meaty foods, like crustaceans and shellfish. Most can be found in the produce department of your local grocery store. Larger pieces of food can be cut up into small pieces and frozen, then defrosted in cool water dosed with vitamins purchased from the aquarium store. I use the Zoe brand, but there are many others. Shellfish can be smashed with a hammer or pried open wide enough for the puffer to get its head in. Its teeth will scrape against the shell when getting the meat out.
Examples are:

* Mussel
* Cockle
* Krill
* Prawn
* King Prawn
* Crabs and crabs’ legs
* Bloodworm
* Blackworm
* Silverside

You can also feed live foods, such as:
* Snail (Many puffer keepers breed their own snails)
* Crab
* Crayfish
* Shrimp
* Earthworm
* Cricket (occasionally)
* Mealworm (occasionally)
* Bloodworm
* Blackworm

Then there is freeze-dried food. Krill, plankton and bloodworms are available, and should be soaked in vitamin water, so the fish don’t suck in air at the top of the tank when feeding. Puffers are adept beggars, so try not to overfeed them. Feed only enough for a slightly rounded belly, one time per day, skipping a day per week for fasting. I feed my adults every other day.

Identifying the Tetraodon biocellatus
Puffers are consistently misidentified and mislabeled by suppliers and shops. Many Figure eights do not have an 8-shaped mark on their back. The most consistently identifiable marks on the Figure 8 puffer are the two black ocelli, or eyespots, on each side of the fish. One in front of the caudal fin and one below the dorsal. Eyespots have developed in many animals to fool predators into thinking the back end is facing them, so the prey won’t be approached from behind. This is how the Figure 8 gets its scientific name — Biocellatus means twin spot!

Figure 8 puffers only grow to around 3 inches. If you hear of one that is much larger in size, you can assume it is actually the Ceylon puffer (Tetraodon fluviatilis), which closely resembles the biocellatus in body pattern, except for spots on it’s belly and the much larger size it grows to.

Choosing and Caring for Your New Puffer
I like to purchase all my fish as juveniles and raise them up properly, with good, meaty, vitamin-packed foods, to make them into healthy adults. Currently, I have two Figure 8s, sharing a 29 gallon tank with a few mollies (to clean up the hair algae problem I had) and a dragon goby. I am relieved to see they are not picking on the slow-moving goby. I believe them to be picking off many of the molly fry, which is fine for me. It is unfortunate that I found out too late what great jumpers they are — I sadly lost 2 of them when they jumped out of small openings in the cover of their tank. Now I know to keep every opening — however small — covered!

I do not recommend keeping Figure eight puffers with other species of puffer. Many aquarists claim to have successfully kept them with Green spotted puffers (Tetraodon nigroviridis). That combination may only work for a short time, while both are juveniles. Eventually, the nigroviridis gets meaner, three times as large and will requite a much higher specific gravity, even marine conditions as an adult. Sadly, a common story emerges with this combination: One day, everything seems fine, the next day; you find your precious Figure 8 puffers dead. It’s a combination to avoid.

You should look for a puffer that eagerly greets you at the front of the tank. Unfortunately, many puffers at stores are kept in improper, overcrowded conditions, may have bites and frayed fins, and are in generally poor health. Try to pick the healthiest-looking one and if they all look poorly, pass on them — and complain to the shop owner! Ask to see your prospective fish eat and check that there is no Ich on the body and fins (Ich looks like white spots of salt have been shaken on the fish). If it eats, does not look emaciated, swims actively and looks generally healthy, then take it home!

The puffer can be easily treated with a gentle healing product like Melafix for bites and frayed fins, and heal quickly in a clean, cycled tank. Be sure that the person catching your fish scoops it out under water with a container, not a net, because if the puffer puffs when out of water, it can fill with air it cannot expel on its own.

This can become deadly for the puffer, unless the air is “burped” from the fish’s stomach, by holding it upright, with its head under water, gently shaking it back and forth until the air is expelled. Puffing is a natural defense mechanism, pushing its spines outward and making it look larger than it really is. Do not try to scare your poor puffer into inflating!

Since there is no formal documentation of this species successfully breeding in captivity, you can assume these are wild-caught puffers. Many wild-caught fish come to us with internal parasites. Internal parasites should be treated internally, so it is important to be sure your puffer is used to the dead foods you are offering it (fish in the wild eat live foods), before treating their food with medication. If you are having difficulty with the transition to dead foods, you can try soaking the food in garlic, or bounce the food on the end of a thread in front of the fish, to make the offering appear to be alive.

So if you are looking for a new addition to your hobby, a colorful, comical, compact fish and you are willing to go the extra mile to maintain a brackish water system for it, then this just might be the perfect fish for you!

Author: Pufferpunk, aka, Jeni C Tyrell

Published by

Jeni Tyrell, AKA Pufferpunk

<img style="float: left;" src="https://img.photobucket.com/albums/v345/Pufferpunk/Bike.jpg" alt="PufferPunk on her Harley" /> <p>It all started when my parents couldn't afford a television, so Mom put me on top of the clean laundry in the basket to watch my Dad's fish. The rest is history! I have been keeping fish for over 27 years now & worked in the industry for about 8.</p> <p>I have had as many as 11 tanks running, ranging from 2g (ghost shrimp gut-loading/snail breeding bowl)-125g (fahaka puffertank). Here is my experience with puffer species, etc:</p> <ul> <li>12" fahaka puffer living in a 125g w/a couple of red-tail & rainbow sharks & 2 very large plecos.</li> <li>2 (6") GSPs a 5" Ceylon. They were in a SW tank w/assorted damselfish, a tomato clown & hermit crabs.</li> <li>5 South American puffers & 1 dwarf puffer living in a 50g w/a frontosa, parrot cichlid & royal pleco.</li> <li>3 F8s living w/knights, bumblebees & a dragon goby.</li> <li>Congo (T. miurus) puffer living in a 15g.</li> <li>10g hex w/a juvenile 2", pignose/arrowhead puffer (T suvattii)</li> <li>20g tank with a 4" T. turgidus.</li> <li>20g w/a 4" A. modestus.</li> <li>A lovely 90g planted tank, w/5 assorted discus, loaches, synodontis, plecos & other oddballs.</li> <li>I have been keeping a 55g reef tank for about 2 years, soon to be upgraded to a 90g & am starting another 50g reef.</li> <li>2 55g river tanks. 1 has assorted toads, treefrogs & African clawed frogs. The other has an dwarf African bullfrog, African sideneck, Asian map & softshell turtle.</li> </ul> <p>(Some of those fish have been re-homed or passed away.)</p> <p>Unfortunately, with all those pets, I recently had to give away all 6 assorted box turtles that had a very nice habitat in the backyard but lived in my basement in a kiddie pool during the winter. I've had some of them for well over 10 years.</p> <p>I own a pufferfish website, The Puffer Forum & am on the Crew of WetWebMedia, in addition to moderating & submitting to countless other forums in the past. I wrote all the puffer fish profiles in the most recent publication of the Encyclopedia of Exotic Tropical Fishes, Published articles on Green Spotted Puffers & Pufferfish Dentistry in Tropical Fish Hobbyist magazine & also in WetWebMedia's online mag, the Conciencious Aquarist, in addition to an article on Dragon Gobies there. </p> <p>I am a scuba diver & underwater photographer. I ride my own 1982 custom Shovelhead Harley-Davidson & am an avid tattoo collector. My Jack Russell Terrier (Kalvin the Krazydog) rides on the back. </p>