Keeping Pacus in the Home Aquarium

A Complete Guide to Keeping Piaractus brachypomus

by Mike McEwan

Introduction

When you think of a "tank buster", what do you think of? Redtailed Catfish, Arowanas, Oscars? Maybe, but one of the most commonly kept large fish in home aquariums is another Amazonian Giant, the Red-Bellied Pacu. We all know Pacus as those cute, almost dopey looking giants that eat everything in sight and outgrow their tanks within months. But there's more to them than that, so let's carry on and learn more about my favorite fish. For this article, we will be discussing Piaractus brachypomus, the Red-Bellied (or simply Red) Pacu.



My Pacu Story

I first kept Red-Bellied Pacus about twelve years ago. I was living in Vancouver, BC, Canada at the time, and purchased one from a local pet shop. I knew full well how big Pacus can get, and planned to buy a larger tank as needed. My aquarium at the time was a meager 29 gallon passed down from my brother! I found it odd that the pet shop clerk didn't warn me of the impressive size that these fish could attain, but assured her anyways that I would be able to properly care for the fish.

Before long I had purchased a 135-gallon aquarium, along with two other Red-Bellied Pacus! The original, who I named Charlie, had a head-start in grown on the new pair, and so he was the king of the tank. Even still, they all got along just fine. However, even a 135-gallon tank is not enough for a trio of Pacus, and, perhaps as some sort of divine sign from the Pacu gods, one day, my 135-gallon cracked. I was there when it happened; the fishes were calm and doing their thing, swimming about the tank, when a crack in the front glass pane appeared out of the blue. It turned out that the home-made stand I had was a little warped, and the stress on the aquarium eventually gave way. That was a lesson I won't soon forget!

Luckily, the tank ended up holding more than half its water, and the rubbermaid bins I had ready weren't needed as temporary homes for my fishes afterall. I had the entire bottom floor of the house to myself, and so what did I do? I did what I always dreamed of doing; I constructed a 650+ gallon indoor pond! I spent the next week or so planning and constructing a pond from scratch, with a wooden frame and black rubber pond liner inside. Of course, I could now only see my fish from an "above water" view, but they loved it. I had to buy several 300-watt heaters and canister filters to maintain the water, but it was well worth it. There's also something great about watching your fish swim and feed from above the water; it was almost like that was the real way to watch them naturally, as if seeing them in their native waters with no glass in between. It was great.

Eventually Charlie passed on and I had to move houses and find new homes for all the other fish, but I will never forget the experience. To this day I love giant Amazonian fishes and will always have dreams of another huge Amazon biotope setting. Oh, and when Charlie passed on, I took the opportunity to weigh him. He was five pounds!

Selecting Your Pacu

Ok, so you have a large enough tank of at least 135 gallons or more in order to properly house a Pacu; now what? First off, keep in mind that 135 gallons may not ultimately be enough. Red-Bellied Pacus can reach up to eighteen inches in length, and so you'll want an aquarium at least two feed in depth for the fish to be comfortable.

Now, with that out of the way, you want to select a Pacu that appears healthy, with all its fins fully in-tact, and is a good size compared to its Pacu brothers and sisters in the same tank, who all presumably came from the same batch. If you want, you can even request that the store clerk feed the fish before you purchase, to make sure they are healthy and feeding properly.

Pacus are sold as small as an inch in length. Specimens this small have little black spots on their bodies. These spots disappear once the fish grows to a few inches in length, which will only take a couple of months! In my experiences, Pacus grow over an inch per month. You may want to purchase one or several, depending on your tank size. Pacus, as characins, are schooling fish in nature, but as they mature and space in the aquarium gets less and less, they can actually stress and fight amongst each other for territory, so keeping them in groups is not always an option.

You can often find Red-Bellied Pacus that have been given to a pet store by an unprepared owner who didn't know what he or she was getting themselves into when they purchased their cute little one-inch fish just months prior. You may want to give one of these guys a good home!

Decorating the Pacu aquarium

Let's face it, Pacus can be destructive to your tank decor. Driftwood can be bumped around and heaters can even be broken. Thus, a nicely-decorated aquarium is not really required. These guys are too big to make much use of caves or shelters. A sandy substrate and some big rocks are all that's necessary. More concern should be given to the size of the tank, the water qualities and the lighting.

Water chemistry

Pacus, coming from the South American Amazon, prefer their water to be soft and slightly acidic, with a pH in the 6.2-6.6 range. However, it is advised that you check the water in the bag when you purchase your Pacu. The pet shop may have specimens that have spent their lives in a neutral pH around 7.0, and you may opt to keep it that way. Anything in this range should be okay; be more concerned with a steady pH that doesn't fluctuate. Keep the temperature in the 75-82 degree range, and use dim lighting. Pacus are shy fish that don't like a lot of commotion around them, and slightly dimmer lighting will help ease their nerves.

Tankmates

Just how big of an aquarium do you have? The truth is, with your Pacu's inevitable adult size, there may not be room for much else in the tank. Pacus are generally peaceful, especially if given enough tank space and are not kept with anything that will challenge them for territory. Adult Silver Dollars should be ok; smaller ones may be eaten as a snack. Oscars and other similarly-sized South American Cichlids usually do okay in the Pacu aquarium as well. And of course, there's always room for a large Pleco. If you're not concerned with staying "all amazon" in your tankmate selection, then you can look at Tinfoil Barbs or Kissing Gouramis.

It should be noted that Pacus often vary in terms of aggression level. If they are fed live or meaty foods, especially as youngsters, they will often become aggressive towards their tankmates. Sometimes they're just bullies because they can be, but they will often outgrow this with age as they get slower-moving and more passive, provided they are given enough swimming space to be comfortable.

What to feed your Pacu

Pacus are omnivorous and will eat just about anything. As mentioned, you may choose not to feed your Pacu live foods as it can promote aggression. Younger specimens may be fed a diet based primarily on staple flake foods, but as they grow larger they will need to be given pellets. Supplement your Pacus with vegetable matter; Pacus love their veggies! Lettuce is appreciated. Try zucchini slices as well. Fruits such as grapes may also be readily accepted. Feed your Pacu a wide variety of these foods and they will love you for it!

In closing

It should be stressed that it is your responsibility as an aquarist to provide a fish this large with a good home. If you cannot properly care for a Pacu, then they are not the right fish for you. Taking Pacus back to the pet shop mere months after purchasing them because they've outgrown their tank is not an experience that anyone should have to go through, but it is unfortunately all too common. Research, research, research. Reading this article was a great start, and there is a lot more information out there. Post on the forums and ask people for their help and suggestions; a lot of experienced aquarists have kept Pacus at some point. If you are ready to bring a Pacu or Pacus into your home, then congratulations! These are my favorite fish and are generally loved by anyone fortunate enough to properly house them. Good luck!