Eyespot pufferfish (Figure-8 puffer)

1) Where they come from (quick backstory)

Figure-8 puffers (Eyespot puffers) come from slow-moving rivers and mangrove-y areas in Southeast Asia. You’ll see them sold as “freshwater puffers,” but in the wild they’re often around brackish-influenced zones, so they’re used to changing conditions and lots of nooks and crannies.

2) Setting up their tank

These puffers are small, but they’re not “small tank” fish. They’re busy, curious, and they like having a territory. A cramped tank makes them nippy and stressed, and stressed puffers get sick fast.

• Tank size: I’d start a single one in 20 gallons (long footprint helps). For a pair or a small group, think 30–40+ gallons with lots of line-of-sight breaks.
• Filtration: strong biofiltration, gentle-ish flow. They’re messy eaters, so you’ll appreciate extra capacity.
• Decor: wood, rock piles, caves, and dense plants (or tough plants). Break up sight lines so they don’t stare each other down all day.
• Substrate: sand is great if you can—easier on them and looks natural. Gravel works, but sand makes cleanup and feeding easier in my experience.
• Water changes: frequent smaller changes beat “big rescue changes.” Puffers notice swings.

3) What to feed them

Figure-8 puffers are little predators with a big opinion about food. Many won’t touch flakes, and even if they do, you don’t want a dry-food-only puffer. You want crunchy foods in the rotation to help manage tooth growth.

• Staples I’ve had the best luck with: snails (ramshorn/bladder), frozen bloodworms, frozen mysis, chopped shrimp, and bits of clam/mussel.
• Crunchy rotation (for teeth): small snails, unshelled shrimp pieces, clam on the half shell (tiny portions).
• Foods some take: live blackworms, earthworm chunks (rinse well), krill (go easy—can be rich).

Feed small portions and watch them eat. Puffers are messy, and leftovers rot fast. I like using a small feeding dish so food doesn’t vanish into the substrate and spike your ammonia overnight.

4) Behavior and tankmates

They’re smart. Like, “come to the glass when you walk in” smart. They’re also little sass machines. Some are angels, some are fin-shredders, and the same fish can change its mind depending on tank size and layout.

• Personality: curious, food-driven, can be pushy at feeding time.
• Nipping: very possible, especially with slow fish or long fins.
• Territory: they’ll pick a cave or corner and defend it.

If you want tankmates, think fast, tough, and not-too-tempting. Even then, have a backup plan (spare tank or divider). Plenty of people end up deciding these are best kept as a species tank, and honestly it makes life simpler.

5) Breeding tips (the realistic version)

Breeding figure-8 puffers in home tanks happens, but it’s not something most people stumble into by accident. Sexing them is tricky, and they can be rough on each other if the tank is tight.

• You’ll want a bigger tank with multiple caves and heavy cover so a female can get away from a persistent male.
• Condition them with varied meaty foods (snails, shrimp, worms) and keep water super clean.
• If you see pairing behavior and cave-guarding, don’t mess with the tank—stability helps more than tinkering.

6) Common problems to watch for

Most figure-8 issues boil down to three things: dirty water, the wrong diet, or stress from tankmates/tank size. They don’t always show early warning signs, so you have to be a little paranoid (in a good way).

• Overgrown teeth: if they stop eating, miss food, or their mouth looks “beaky,” you may need more crunchy foods (snails!) and a diet reset.
• Ich/parasites: puffers can be sensitive to meds, and many don’t handle salt/medication combos the same way other fish do. Quarantine new fish/foods if you can.
• Bloat/constipation: often from overfeeding rich foods or too many worms. Try smaller meals and mix in shelled foods; watch for swelling and floating.
• Fin damage: usually from nipping (tankmates or other puffers). Add cover, reduce stocking, or separate.
• Ammonia/nitrite spikes: messy feeding + small tanks = trouble. Test kits save puffers.