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Often sold as juveniles and mistaken for the Piranha, the Pacu soon outgrows all but the largest aquariums. If you are willing to meet its space requirements its' personality and ease of care will offer many years of enjoyment. These are pictures of Debbs Pacu at 17"

Quick stats: Listed tank sizes are the minimum Size: 3 feet, that’s right 3' !! (92cm) Tank: 75gallon + when small Strata: Bottom, middle PH: 6.5 to 7.0 Hardness: Soft to medium. dH range: to 20.0 Temperature: 72ºF to 82ºF (23-28°C) Classification: Order: Characiformes Family: Characidae Subfamily: Serrasalminae Genera: Colossoma Species: macropomum

Common name:

Black-finned Pacu , Pacu and Tambaqui

Image gallery:

Additional species photographs

Discuss:

Badmans' Forum

Distribution

Brazil, South America

Similar in shape to the piranha and part of the source of the confusion the pacu is a tall, laterally compressed fish with large eyes and a slightly arched back

Body color is basic black to gray with spots and blemishes in its mid body. All the fins are black and the pectoral fins are small.

Recommended Aquarium size - They grow fast so my recommendation would be to start out in a 75+ to 300 gallon. If you start out in a smaller tank you will be upgrading every few months.

Water - do best in softer, slightly acidic water. Between 6.5-7 is good.

Temp.- 78-82 degrees Fahrenheit (23-28°C)

Diet - Pacu's are reported to be herbivores but are in fact omnivorous (eats anything).
Sinking food pellets such as HBH's Super Cichlid Sinkers or Spirulina Pellets are very good foods to keep a healthy Pacu. They need a balanced diet so giving them veggies such as romaine lettuce, peas, carrots, celery, zucchini and fruit such as nectarines, apples, grapes are recommended in their diet. Algae wafers are a favorite also.

Life Span- This fish lives for twenty + years, depending on species and care given.

In the wild, they interact and play with each other, indicating they are indeed a schooling fish. However, as they mature, many varieties of Pacu become more solitary and no longer need same-species companionship. Pacu can, like most fish, be kept with fish with similar care requirements and temperament. This generally means fish that are going to get large and that are neither too aggressive nor too timid, as the Pacu will occasionally nip fins.

Personality of a Pacu - I can only speak from my experience with our Pacu over the last 2yrs.
This Pacu is a what I'd call a ";Gentle Giant". He is in a 180 Gallon tank with a variety of Cichlids. He's the least aggressive of them all. Yet he won't be bullied by any fish. When a cichlid tries to nip him (from the back end ) I've seen the Pacu turn around and chase the fish away. He sometimes seems to make a game of this, it's very hard to explain but I've seen him chasing a fish in circles but only to end up turning his back on the fish and waiting to be nipped at again. Here is another example of his personality. When I clean his tank, he loves me to rub his sides as he swims around my hand over and over again. He has personality, likes and dislikes and shows his vulnerable dependency upon us for companionship, food and care.

He is as most Pacu's are known for, skittish. Any fast movement or vibration will cause a panic like reaction from the Pacu, sometimes resulting into banging into the glass, heater or decor. Pacu's are known also as "tank busters". I can relate to that, and even though my Pacu hasn't busted a tank yet, I know with his massive strength, bulk, and panic attacks he can easily break glass.

My Pacu is 17" and I believe almost 3yrs. old. When we first received this fish from a friend at approx. 7", he was mistakenly Id'd as a Pirana. He sure looked like one!

At a young age, Pacu's look almost identical to their cousin, the Piranha. The easiest way to tell the difference is that a piranha's lower jaw will jut out much more then that of a pacu's. As the Pacu grows, the differences will become much more obvious. He will become deep bellied and wider.

Lastly I'd like to warn people, hobbyist, fishkeepers. Do NOT buy this fish if you are not planning on keeping him full term. He will require a 300 gallon tank within a few years. This is a fish that is easy to keep in the right conditions, BUT, he also is a fish that needs room to grow, and grow and grow. I'm very upset that this fish is sold to the public without a warning of the max growth size. In one store I had seen them state his max. size to be 12". I wrote them telling them the stats of this fish and was thrown off by an ignorant reply "we sell according to consumer command." Well the majority of consumers would not wish to have a fish that grows to 3' if they knew about it, unless they were heartless people. That's my reply, and that's why I'm putting this on this board. If you've a heart, you'd not buy this fish unless you plan on a 300+ gallon for him to live a full, healthy life.

I forgot to add that the Pacu's do and will eat small fish without hesitation. This is a warning, not a recommendation.

I also would like to add that at 17" long, his height is 11" and width almost 2". This is just and example of the impressive girth these fish have. They are now being raised in huge fish farms throughout the world as a food fish.





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Young stay in Black waters of flood plains until maturity, adults in open water and flooded forests.

Breeding:

Sexing -The male's red coloration is much brighter than the females, and his dorsal fin comes more to a point.

Little (or nothing) is known of their breeding habits, due to the large size and space requirements

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From: Kris Williams Date:1/2/2008 Having always wanted a large fish, three and a half years ago I bought a baby Pacu. "Carl" as he was soon named was tiny at the time, no bigger than a nickel. Well, three and a half years later, he is easily 13 inches long. I feed him a floating large cichlid sticks, as well as a variety of just about anything else vegetable wise. Even large chunks of banana disappear right down him with no problem at this stage. Make no mistake, this has got to be the fastest growing fish I have ever raised. While he started out in my 29 gallon community tank when he was a baby to avoid my larger more aggressive fish, I always knew he would move up through the various sized tanks I had throughout the house. By the time he was 4 months, he was nearly 5 inches long, and into my 55 gallon South American biotope tank. Not much longer, and he inherited my 100 gallon, so forth and so on. As far as personality goes, he really is my favorite fish. If I'm within eyesight of the tank, "Carl" watches the "Food Bringer" (me) with great interest. When he was smaller, only 6 inches, he did bite me once in the arm as I cleaned the tank. Keeping in mind that they are relatives of the piranha, and that they DO have teeth, he actually hurt me a bit. I'm glad to report that only happened once, and now he'll let me stroke his sides when I clean the tank. I'm sure he had just felt cornered or scared at the time of the incident, being a little sketchy as they are. However, he never has hurt another fish, and to this day, he resides with my 4 inch long female Frontosa who, sadly, I had to evacuate from another tank due to an overly zealous male. "Carl" doesn't mind her company in the least. I will say that I have only ever kept this fish in acrylic tanks. Seeing his occasional panic attacks (far less frequent as he grew older) there is no doubt in my mind he could have easily destroyed a glass tank. A vision, at the very least, of a glass tank's top being hurled to the floor would have definitely occurred during some of his more spectacular tirades. All in all, as I said, he is my favorite fish, and I am glad to know that he will be with me for a decade or more. If you're not committed to giving them the space, though, don't buy one. Remember, that dime sized silver little fish is going to be a large black monster within a few years. From: Diane Date:4/19/2007 I have just bought my first pacu. I got it at Walmart, but I was smart...I seen the fish and was interested in it so I went home and did some research, BEFORE BUYING THE FISH !!! As a pet owner it is OUR responsibility to find out about the fish/ pet BEFORE buying it !! I knew how large he would get,what size tank he needed etc. before I brought him home. Needless to say, I love him !! He's still small, only maybe 2 inches or so. I've had him only a few weeks but he's growing everyday. I can see how much he's grown already. He loves little pieces of grapes, apples, flakes, and shrimp pellets etc. He's not very keen on algae tablets though....lol. Anyways, just remember it's OUR responsibility to research and ask questions BEFORE getting fish or any other little critter...they don't want to be pawned off or dropped in a lake somewhere when their owners decide their "too big" ! Stop blaming pet stores and be responsible pet owners ! From: Bill (UK) Date:1/16/2007 About 4 years ago, a bucket appeared at my house with (apparently) an unwanted 8-inch piranha in it. I had a 5-foot long tank spare so he came to live with me, great happy fish for a while, just fed him fish and meat, seemed happy, I’d never heard of a pacu at that stage. I’d noticed a few things about him that weren’t quite right, didn’t have the protruding jaw, his teeth were short and stumpy instead of sharp and serrated, his eyes sat slightly lower in his head and he’d lost the red belly, but I’d been told it was a piranha and so accepted it. I excused these things, thought he’d get the jaw and teeth with age, and I know female red bellied piranhas lose the red colour when breeding. It was only after almost a year later, when he found it difficult to turn round in the 12-inch wide tank. I know piranhas grow approximately 10 inches; he’d got to be 11. I started looking for a new big tank, luckily I found one on ebay so big, nobody else would want it, and at very low cost, I only just got it in my house. Being a corner tank (approx. 150g), the shape makes it much more roomier for him than an elongated one, he loved it and perked right up. A year later with people always remarking on how he was growing, but seeing him constantly I couldn’t tell. On measuring him 16 inch now, started researching what in fact he was with no clues. Personally I was pleased to find out what he is, just wish I’d known from the start. He is now 20 inches long, a foot high and 3 inches thick, shares the tank (believe it or not) with a school of 30 x 1 inch long neon tetras (he doesn’t bother them at all, it’s amusing watching them going around the opposite sides like 2 magnetic +’s, and they eat all of his crumbs, keeping tank clean). He’ll eat virtually anything, but has his likes/dislikes as anyone does. I buy no special food for him; he has what I have (except fats and sugars etc.), all fruits, vegetables, meat, fish, nuts, cooked or uncooked. He’s like a puppy – bright, cheerful and playful, loves attention and gets very excited (to the point you’ve got to leave him alone to calm down). You cannot have many decorations or ornaments with these fish, for obvious reasons, I just have a huge realistic looking plastic plant in the middle floating to the top rooted down with fishing line, not unlike kelp, and be careful with things sticking out or floating from pumps, filters, heaters etc. they chew anything and with a mouth like pair of nut crackers, if you prefer to keep your fingers, take heed, as a friend found out the hard way a few months ago, despite the warning, what a mess, it’s almost healed now though, and with a few more months of psychologist counseling the nightmares will ease and she’ll lead a normal life again. Seriously though, I’ve kept so many fish through my life and I’d safely say the pacu is so different to anything I’ve had before, such a pleasure and easy to keep, he’s called Little Bigman, and he seems to recognize my voice. He could potentially double his size and live another 20 years, if he needs more space sometime, I’ll cross that bridge at the time, but I’m very attached to him. I’ve been in a wheelchair some years now and he’s great company when I’m at home. From: Lilly Date:12/20/2006 I was reading through the comments to the pacu profile and noticed that several people commented about the lack of information LFS gave them about how big pacus get, and how the store's total length description of the fish are inaccurate. I use to work at petsmart. I was aware of the size that pacus got. I asked my manager if we could change the tag to the correct total length. She told me we couldn't because all the stores have to say the same thing on their tags. She wasn't willing to call cooperate to ask them to change the length of the pacu to the correct size. We had the same problem with other large growing fish. Like the clownfish and the iridescent catfish. I asked my more fish-savvy co-workers about what they tell people about the pacu and what to do in my situation. They nodded their heads in agreement that description for the length of the fish was incorrect and not good for people who didn't know better but they couldn't do anything about it either since my manager wasn't willing to. They told me that they would just tell customers that the pacu grows several feet long and should only be houses in the largest tank the buyer can afford. So this is what I began to tell customers also. Fortunately, I didn't get many people interested in buying the pacus at our store because people thought they were piranhas. When people did for me to bag this fish up for them I found that most of them either didn't believe the fish really got that big, or didn't care that they got that big because they believed in the "fish only grow to the size of their tank" myth. When I tried debunking that myth they became agitated and still wanted the fish anyway. It was that store's policy the ask every customer what size tank their fish were going to be put in and what fish were already in there. Since the first question I always ask a customer who wants a fish is about the size of their tank, I always knew if the fish was compatible for them or not. Ironically, none of the people that approached me for that fish had a large enough tank. Our store also could refuse the sell a fish if they knew it would be kept in inhumane conditions. I had to turn those people that couldn't accommodate the fish away. We did the same thing for small animals. I've heard at other petsmarts they don't do this. I was glad I was working in a store that could at least could do that much for the pets they sold. Even if it was "just a fish". For those of you consumers out there I encourage you to write to petsmart, and other pet stores. Ask them to change the description to the correct information. Customers have more power over the situation than the people working at the store do. Badmans Note: Lilly and all interested parties you will be happy to know this effort is well underway, please visit the No clowns in a cube website for ways YOU can help the effort. From: Brittany Date:10/24/2006 I purchased 1 Paccar about 8 months ago from Walmart just thinking he was a cute smiling LITTLE fish I got him and he was less than 1/2 an inch long they told me he'd be fine in the 75 gallon tank I had at home and now he is 8 almost 9 inches and I feel bad that I don't have a bigger tank for him I plan on upgrading to a 300 gallon tank with my next few pay checks because I love him he has got to be the smartest of all my fish and has the most personality out of them too I wish pesters and Walmarts would tell you how big these fish really do get I think its sad and cruel to the fish for them to tell people he shouldn't get more than 10 or 11 inches I've not had mine a year and he's almost that big his name is Sammy and he loves fresh peas and carrots he also gets squash every once in a while as a treat he has a few friends 3 rather large tiger barbs Sue Stan and Earl 1 huge red tin foil barb Stewart a blood parrot with 1 eye Mable and Jack dempsey named Rainbow From: Matthew Archer Date:07/22/2006 I have had 2 pacu’s for a little over a year they were an inch and a half when I first got them. I was aware that they would be very large. They have had a few roommates from time to time I had them in a 60 gallon with an Oscar and a convicts when they got too big I bought them the 240 gallon I have now I only kept them and 1 green plecostomus and 1 chocolate albino plecostomus I cannot believe the amount of personality that these fish possess I am a very happy owner and plan to have them well over a decade. I hate the fact that Wal-Mart says they grow to 10" they should put in fine print ( within first 6 months ) I know that Petsmart use to have them labeled at 22" and now at 24" my smallest one is 24" my larger 28" it is amazing how there shape changes after they get that long they start growing taller as well I have found a picture of one that was caught in South America that was 5 foot long 3 foot tall and 9 inches wide they are huge and supposedly good eating ( stay away from mine please ) it is too bad that there is little documented info about them I am earning my MASTERS Degree in Ichthyology and Conservation Biology studying many fresh water fish (mainly largemouth bass) and I wish there were more publications on this wonderful fish. Oh ya my pacu’s are named Gumby and Pokey From: Greg Hall Date:03/17/2006 I have four Pacus that I bought about 3 years ago. They are very hearty, and now occupy a 150 gal. aquarium. They are actually too large, but I have no choice for more room for them. They eat canned vegetables, which are easily obtained, and healthy. Their favorites also include nuts of just about ant kind, but they tend to foul the water tremendously. Since Pacus have little or no teeth, small pieces of the nuts break off when they eat them, and remain in the tank or get trapped in most store- available filters. I have built a 32 qt. charcoal and bio-filter, coupled with a 20 qt. fiber filter , just to accommodate the fish and their food/waste issues. It cycles the tank about twice an hour. They are interesting but a challenge. If you want to give your Pacus a treat, substitute one of their regular meals with red, sliced beets. They are inexpensive, and you can open a can, drain and rinse all of the red juice, and drop the slices in for them. They can bite the soft beets, and leave little or no pieces to be cleaned up. My Pacus love them. From: Al Date:02/24/2006 I feed my pacus a different type of food each day twice a day to keep them healthy normally I will feed them chicken beefheart peas koi food large cichlid sticks and shrimp pellets the only problem when feeding them that much is you need a good bio system to keep your ammonia at zero I keep my 22in 15in 13in pacu in a 125 gallon moving to a 355 next week they need it. CLICK HERE FOR MORE COMMENTS

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