Figure 8 Puffer

Geographical Origin & Biotope:

*Dichotomyctere ocellatus* is native to Indochina, Malaysia, and Borneo. It inhabits jungle-covered river estuaries, mangrove areas, and lower coastal rivers heavily influenced by tides and the saline wedge. The water in these regions is tannin-rich but with a moderate, constant salt level, an environment vital for its osmotic balance.

Taxonomy & Morphology:

Previously classified in the genus *Tetraodon*, the Figure 8 is immediately differentiated from the Green Spotted (GSP) both by size (exactly half) and by the dorsal pattern. The head has enormous bulging eyes with independent mobility. The beak possesses the 4 fused incisors typical of the family. Often, when observing something closely, it surprisingly and comically crosses its eyes or looks with intent awareness.

Social Behavior:

It is a profoundly introverted fish compared to others, but endowed with exceptional acumen. It will spend hours inspecting a single grain of sand to see if it hides food. It gets bored easily in bare tanks. Despite its innocent snout, it will deliver lethal bites if annoyed or hungry.

Coloration & Sexual Dimorphism:

The livery is marvelous: the background color of the back is golden yellow or light mustard green, upon which thick, irregular black lines (like a maze) stand out. The key to identification lies on the sides of the back, where these black lines always form two large ocelli, or black spots circled in yellow or white, which from above resemble a figure "8" or an eye (hence the common names). The belly is a blinding white. There is no visible sexual dimorphism.

Tank Setup:

Unlike the Green Spotted Puffer, which requires a near-marine habitat in adulthood, the Figure 8 is a low-salinity estuary specialist. Water density must be rigidly and constantly maintained between 1.005 and 1.008 specific gravity using synthetic marine salt (table or freshwater aquarium salt is useless as it lacks oceanic trace elements). A 60-80 liter (15-20 gallon) tank is excellent for comfortably housing a single adult specimen. The setup must be a true maze: use large stones, tangled driftwood, or hidden PVC pipes to force it to "patrol" rather than see from end to end. A Puffer in an empty tank will fall victim to boredom and stress, manifested by obsessively swimming up and down the glass (glass surfing).

Diet & Feeding:

Being equipped with dental plates that continuously grow throughout their lives, the absence of crunchy food will lead to fatal malocclusion. Do not feed pellets. A thriving parallel, separate culture of freshwater pest snails (Physa, Ramshorn, or small Melanoides) is your number one ally: they should be dropped into the tank daily. Small specimens love frozen bloodworms and brine shrimp, but as they grow, snail shells and small crustaceans (mysis) must become the predominant part of the diet to ensure teeth wear.

Water Quality:

The combination of high metabolic waste, absence of scales, and messy eating habits make this small fish a ticking time bomb for ammonia. Oversized filtration (but with only moderate current, as they are not excellent upstream swimmers) and 50% weekly water changes are mandatory to dilute nitrates, which, if too high, will fade its belly color from snow-white to dirty grey.

Compatibility & Tankmates:

It is almost categorical to keep them alone in species-only tanks. They have a sadistic predilection for long fins (Guppies, Bettas, Angelfish would be stripped of their fins overnight). Even fast Danios would eventually tire and get bitten. Only in very long brackish tanks (over 120 cm / 4 feet) with endless hiding spots is it possible to keep them with small Bumblebee Gobies (*Brachygobius* spp.), which, inhabiting the rocky bottoms, tend to be ignored by the Figure 8 patrolling mid-water, but the risk remains.

Aquarium Breeding:

Virtually impossible to replicate for hobbyists. Even professional facilities do not have a reliable protocol. This makes all specimens on the market wild-caught: pay close attention when purchasing to ensure they are well-fed and lack the fatal "sunken belly," a sign of lethal internal parasites.

Risks & Diseases:

A sunken belly is the primary clinical sign of intestinal parasites (flagellate infections and nematode worms), extremely frequent in wild-caught specimens. As soon as brought home, a preventative round with medicated foods based on praziquantel or metronidazole is the best insurance policy. Keeping them in pure freshwater for more than a few weeks causes osmotic stress, immune weakening, and lethal explosions of fungus or bacterial infections.