Monster fish keepers make the worst mistakes.

I just dragged myself home from twelve hours of scrubbing massive acrylic tanks, and my shoulders are absolutely burning. I poured a drink and sat down, but I keep seeing the same nonsense online. People buy these tiny, cute fish for ten bucks.

They throw them in a basic setup. Then those fish turn into literal giants that need huge fish tanks just to turn around. Arawanas grow to forty inches long.

The Arapaima gigas is literally the largest freshwater fish in the Neotropics. It is not a cute pet. It is a water-breathing dinosaur.

The Mistake That Still Makes Me Cringe

Back in 2014, I thought I knew everything about large predator fish. I bought a tiny, adorable walking catfish and dumped him into my mixed community setup. I went to sleep feeling like a true professional.

I woke up the next morning to an empty tank. That fish had literally inhaled everything else, because walking catfish can reach over three feet long and have mouths big enough to consume waterbirds whole. I stood there in my boxers, holding a plastic net, feeling like the biggest idiot on the planet.

If a smaller fish fits inside a predator’s mouth, it is legally lunch. Science.

Why I Think You Should Need a Permit

Here is my highly unpopular opinion that always starts fights at local club meetings. Nobody should be allowed to sell you an Arapaima or a Pacu unless you have a specialized permit. You just shouldn’t.

Monster fish keepers love to brag about their massive pets, but most of them shove thirty-inch Black Doradids into glass boxes that are way too narrow. A sturgeon catfish needs an enclosure more than twice as wide as its barbels just to extend them fully. It makes me sick.

True monster fish keepers understand that most of these species live seven to ten years or more in captivity. You are making a decade-long commitment to a giant eating machine.

Go Do This Right Now

Stop dreaming about buying that massive predator you saw at the shop today. Grab a tape measure right now, walk over to your space, and map out a footprint for an eight-foot tank. If you cannot physically fit that massive box in your living room, close your wallet and pick a different species in the next ten minutes before you make a terrible mistake.