The Tetraodon MBU puffer is the largest freshwater species of puffer fish. Getting 22+ inches in a home aquarium. With the fish getting so big, most aquarists struggle to keep one healthy. While my largest one has only gotten to 22 inches, I suspect they’ll grow to as large as 30 inches depending on how they are raised throughout their extended lives.
The first question is always what size of an aquarium? Some say 300 gallons, some say 1000 gallons etc. The reality is the foot print is much more important than how many gallons. With a fish that gets to 30 inches, a tank say 8ft long and 4 ft front to back that is only 2 ft tall works much larger than a tank that is 4 ft tall, 8 ft long and only 2ft front to back. More area to swim will always be better and the more gallons of water generally makes waste management easier in an aquarium.
My current aquarium for my second MBU puffer is 72x48x24 inches tall which is 360 gallons. The MBU itself is about 13 inches currently. My previous MBU was 22 inches before he passed at 5 yrs old. He passed much too early to a wild caught disease with no known cure as the necropsy revealed. It had made lots of lesions on his heart and other organs and taxed its system over time.
As for waste management, I currently change 100 gallons of the 340 gallons daily. This keeps nitrates at 0 in the aquarium. This is controlled by an automatic water change system so that it never gets missed due to illness, holidays etc. Live plants are also beneficial in the reduction of waste in this aquarium. When you have a 22 inch fish feeding on 6 to 8oz of food a day, their feces is the size of small dogs.
Their diet is another difficult aspect for most owners. They need most of their diet to be shelled foods. Things like clams, muscles, snails, crayfish etc are all important pieces. This helps keep their oversized teeth also known as a beak trimmed down. I feed my MBU puffers shelled foods 5 days a week and softer foods 2 days a week. Things like cocktail shrimp, fozen blood worms etc. These are soaked in a vitamin supplement. I haven’t had luck getting any of my MBU puffers on dry foods after trying for years. I do know others who have been successful however. Be prepared for a food bill that is up to $10 a day when they get large. The $300 monthly is akin to keeping a very large dog on a specialized diet. A variety is important as it’s too easy to rely on only one type of food and develop vitamin deficiencies.
Live foods help stimulate the hunting instincts of the puffer, but can also bring in parasites. Also, there can be danger from claws from crayfish and fiddler crabs etc. It is recommended to cut one of the claws before feeding so the live food can’t clamp an eye of the puffer.
One benefit to feeding lots of shelled foods is that the shells can be left in the aquarium and it helps buffer the water. Almost forming a crushed coral like substrate. This helps buffer up the pH and alkalinity of the water. As they get bigger and eat more, more and more shells litter the bottom. If you’re using sand, you can use a coarse net to scoop up shells and sand and sift the shells from the sand to remove them if the bed is getting too thick.
A pH of above 7.0 should always be maintained. I’ve kept mine at 7.4 pH typically, if my natural tap water was higher I would keep it there as well. With so much water being changed it makes more sense to adapt the puffer to the tap water pH plus shells than it does to alter it. Especially with automated daily water changes.
The puffers have excellent vision and will grow to recognize their owners from across the room easily, which makes this puffer a great wet pet. As they get larger their eyes get further and further apart from each other. This causes the puffer to have to look at its food from the side, then line itself up and then eat it. There are times when tank mates swim in for food at the right moment and can be eaten by mistake. This happens it seems like once every 6 months or so.
Casualties can be lessened by choosing the right tank mates. In general, you want to keep very peaceful and passive tank mates. However, things like loaches and corydoras also love clams, and other meaty foods and can go for food at the wrong time. I once lowt an Ellipsifer Eel from Lake Tang, early on with my first Mbu puffer to this, a mortal wound do the tail end of the eel when they both went for the same piece of shrimp. The best tank mates I have found for my MBU puffers have been fancy guppies, tetras, siamese algae eaters, plecos, rasboras, rainbow fish, roseline sharks, geophagus species etc. Things that didn’t work out well, Flagtail Prochilodus, Giraffe Catfish, basically anything that would touch the MBU puffer or be a pig when it came to food time.
When it comes to décor for a MBU Puffer tank, I recommend avoiding anything pointy. When the puffer is spooked, it can be sent running. A sharp stick or rock can do a lot of damage. I like to line the sides and back of my aquarium with live plants. This provides visual barriers and allows the fish to hide in the weeds if they’d like to. I like to use lots of Anubias sp. and Java ferns as MBU puffers like to move the sand around hunting for snails etc.
For temperature, I run my tank in the mid 70s. I don’t use aquarium heaters, I heat the whole room. Partly because I run a lot of aquariums, but mostly so I can eliminate any heater malfunction from the list of potential killers for a MBU puffer. With an advanced fish that requires so much care, the more you can automate, and problems you can prevent the easier it will be able to keep a puffer healthy long term.
When you move a MBU puffer, you want to keep them under water the entire time. If they puff up out of water they can get air trapped. If they can’t expel it, it can kill them. MBU puffers will stretch and inflate and deflate quickly from time to time in the aquarium. This is normal as long as it’s not related to a stress factor, like a loud noise etc that causes them the stress. I liken a puffer puffing up to a human fainting. It takes so much shock to the system to have a human faint as well as a puffer puff up, it’s purely a defense mechanism.
For more information and to see some of these concepts explained in a video, check out my MBU Puffer species profile video.