Arrowhead puffer

Where they come from

Arrowhead puffers (Pao suvattii) come from Southeast Asia, mostly around Thailand and nearby areas in slow rivers, canals, and muddy backwaters. They are a "sit and wait" predator in the wild, which explains a lot about how they act in our tanks - they pick a spot, watch everything, and ambush food.

Setting up their tank

This species is advanced for one big reason: they are not community fish, and they are not forgiving if you cut corners on space, filtration, or boredom. If you set the tank up around their personality, they're actually pretty straightforward.

• Tank size: I would not do smaller than 30 gallons for one, and 40+ is just easier to manage long term.
• Footprint matters more than height. They spend a lot of time on the bottom and like to claim a zone.
• Substrate: sand is my pick. They root around and it looks natural with them.
• Hardscape: lots of wood, rock piles, and line-of-sight breaks. Give them multiple "caves" even if you only keep one fish.
• Plants: tough stuff or floaters. They can redecorate, and some individuals treat delicate plants like chew toys.

Filtration needs to be beefy. They are messy eaters, and the food they like (meaty, chunky stuff) fouls water fast. I run extra mechanical filtration (sponge prefilter on the intake helps a ton) and I keep a gravel vac handy even with sand.

• Temperature: mid to upper 70s F (around 24-26 C) is a comfortable zone.
• pH and hardness: they adapt to a range, but stability beats chasing numbers.
• Water changes: expect to do them often, especially if you feed heavy. Leftovers and waste show up fast with these guys.

What to feed them

They are predators and they know it. Mine learned the feeding routine quickly and would sit in the same "launch pad" spot waiting for shrimp or snails. The trick is variety and not letting them get lazy on one food.

• Staples I rotate: shrimp (shell-on when possible), chunks of white fish, squid, earthworms, and snails.
• Good treats: live blackworms, live shrimp, and the occasional crab or mussel meat (not constantly).
• Foods I avoid as regular diet: feeder fish (parasite risk), fatty mammal meat, and too much dried/processed stuff.

Snails aren't just food - they're tooth insurance. Puffers' teeth keep growing, and crunchy foods help keep them worn down. You don't need to feed snails every day, but you do want hard-shelled meals in the rotation.

I feed adults small portions once a day or every other day depending on body shape. They beg like puppies, but they can get chunky fast. Remove leftovers within a few minutes - uneaten shrimp turns into ammonia soup surprisingly quickly.

How they behave and who they get along with

Arrowhead puffers are basically aquatic landmines. They're not constantly aggressive like some cichlids, but they have a very clear idea of what belongs in their space, and they can go from "fine" to "I will bite that" with no warning.

• Best plan: species-only tank with one puffer.
• Tankmates are a gamble. Even "fast" fish can get nailed at night or when they wander too close.
• Bottom dwellers (plecos, loaches, cories): usually a bad match. Same territory, and they get bitten.
• Inverts: will be hunted. Shrimp and snails are food, not roommates.

They can be shy at first, especially in a bare tank. With cover and a consistent routine, they usually settle into a pattern: pick a favorite cave, patrol a bit, then park and watch. They are smart enough to recognize you and will come out for food once they feel secure.

Breeding tips

Breeding Pao suvattii in home aquariums is uncommon. They are not easy to sex, and keeping pairs together is risky because of aggression. Most hobbyists (me included) keep them solo, which pretty much ends the breeding conversation.

Common problems to watch for

Most issues with arrowhead puffers come from three places: dirty water from messy feeding, tooth overgrowth from soft diets, and stress from bad tankmate choices. If you stay ahead of those, you're already doing better than most.

• Overgrown teeth: caused by too many soft foods. Rotate in snails and shell-on shrimp.
• Bloat/constipation: can happen with heavy meals. Feed smaller portions and add more rougher foods like snails/worms.
• Internal parasites: wild-caught puffers sometimes arrive with them. Watch for weight loss despite eating and long, white stringy poop.
• Fin bites and wounds: usually from tankmate experiments or cramped setups. These bite marks can get infected.
• Ammonia/nitrite spikes: often from uneaten meaty food. Remove leftovers fast and keep filtration maintained.

One last thing: skip most "puffer meds" advice you see copy-pasted online. Puffers can be sensitive to some medications and dosing. If you need to treat something, identify the issue first and double-check the med is puffer-safe before you dump anything in the tank.