Mekong puffer (bearded puffer)

Where they come from

Mekong puffers (Pao barbatus) come from the Mekong River system in Southeast Asia. Think big, warm, fast-changing freshwater with lots of structure - roots, branches, rocky edges, muddy areas, and a constant supply of crunchy little critters to hunt.

That background explains a lot: they are alert, food-motivated, and they do best in a tank that has breaks in line of sight and feels more like a riverbank than a glass box.

Setting up their tank

This is an advanced puffer mostly because of size, attitude, and mess. They are not a "cute community puffer". Plan the tank around the adult fish, not the baby you brought home.

• Tank size: bigger than you think. I would not bother with anything under 75 gallons for one, and 125+ gallons makes life easier (for you and the fish).
• Filtration: heavy. They eat meaty foods and turn it into waste fast. Oversize your filter and keep spare media seeded if you can.
• Flow and oxygen: moderate flow with strong surface movement. They handle current fine, and it helps keep gunk from settling everywhere.
• Layout: lots of wood, rock piles, and plants (tough ones). Give it caves and visual barriers so the fish can "reset" and not patrol the whole tank like a bouncer.
• Substrate: sand is my pick. They spend time nosing around and sand is easier on them than sharp gravel.

Water-wise, keep it clean and stable. Neutral-ish pH is fine, medium hardness is fine, and warm tropical temps. What matters more than chasing a specific number is consistency and keeping nitrate from creeping up. If you have to choose between fancy aquascaping and easy maintenance, pick easy maintenance.

What to feed them

They are predators with a strong preference for crunchy, wiggly food. You will get the best results with a varied menu, and you will also keep their teeth in check by feeding things with shells.

• Snails (pond, ramshorn, Malaysian trumpet): the classic. I keep a snail bin going so I am never scrambling.
• Fresh or thawed shell-on shrimp/prawns (chopped to size): great staple, good crunch.
• Mussels, clams, cockle (chopped): messy but loved. Rinse first.
• Earthworms and nightcrawlers: one of the best foods for getting weight on a picky fish.
• Crab pieces or crayfish (sparingly): excellent enrichment, but do not overdo fatty foods.
• Occasional frozen foods like bloodworms: fine as a treat, not the main diet.

Feeding frequency depends on size. Juveniles eat more often; adults do better with larger meals a few times a week. Watch the belly and the behavior: a slightly rounded belly after meals is good, but a constantly ballooned fish is not.

How they behave and who they get along with

Expect a smart, bold fish that learns your schedule and begs like a dog. Also expect territorial behavior. They are not "mean all the time", but they are perfectly willing to bite first and ask questions later.

• Best option: species-only. One Mekong puffer with you focused on water quality and diet is a very solid setup.
• Possible tankmates (only in big tanks): fast, sturdy midwater fish that can handle themselves and do not have long fins.
• Bad tankmates: slow fish, long-finned fish, bottom dwellers that cannot get away, and anything you would be sad to see nipped.
• Other puffers: I would not. Mixing puffers usually turns into stress, fin damage, or worse.

If you try tankmates, watch the puffer at lights-out and feeding time. That is when the "it seemed fine" situations fall apart. Have a backup plan (spare tank, divider, or a friend who can take fish) before you experiment.

Breeding tips

Breeding Mekong puffers in home aquariums is not common. Sexing is tricky, pairing can be dangerous, and they do not give you many obvious cues until things go sideways.

If you are determined, the best shot is starting with a group of juveniles in a very large tank with tons of cover, then letting a pair form over time. Even then, be ready to separate fish quickly. Conditioning with lots of live and fresh foods and doing large water changes (mimicking seasonal swings) is the typical approach people try with river puffers.

Common problems to watch for

Most issues with these puffers trace back to three things: dirty water from messy feeding, tooth overgrowth from a soft diet, and stress from tankmates or cramped quarters.

• Tooth overgrowth: the fish stops eating, spits food, or looks like it has a "beak" that is too long. Fix the diet early with more shelled foods. Severe cases need trimming by someone experienced.
• Bloat/constipation: common after too much rich food. Try fasting a day or two and feeding a worm meal after. Keep temps steady and water clean.
• Parasites (especially on wild-caught fish): skinny fish with a big appetite, stringy white poop, or sudden decline. Quarantine new puffers and consider deworming protocols used by experienced keepers.
• Fin damage from nipping: either from the puffer or from stressed tankmates. Usually solved by separating fish, not by rearranging decor forever.
• Poor water quality: cloudiness, smell, rising nitrate, and a puffer that goes dull and hides. Increase water changes, cut back feeding, and clean filters without nuking your bio-media.

If you give them space, structure, and a steady supply of crunchy foods, they are unbelievably rewarding. They have more personality than most fish - they just come with rules you have to respect.