Black pacu? Hybrid?

[Muckfish]

I grew out a group of RB pacu. I kept them in a pool and from above they all looked the same. They are now in a pond and pushing likely 10-12” and two look more like a black pacu. One has the lower half dark coloration and one looks solid black. Does anyone know if hybrids can show these markings or are these possibly real black pacu. I’m just curious for my own general knowledge since I do not know what a true hybrid looks like.
I do not have them in a tank so I can only get shots from above at the moment.

Hybrid?

black pacu?

Black pacu? with red belly for comparison

 

[Deadeye]

Red bellies do get very dark as they age. That is probably the primary thing you are seeing. There probably also is something with dominance.
That said, with a fish so commercially bred I would not be surprised if hybridization or shipping the wrong fish did occur.

 

[12 Volt Man]

looks like normal red bellied pacu to me. they only really have the red belly until around 12-14 inches or so after that its dark grey and silver.

awesome fish!

I had a big one back in the 90s that I raised that was the same as this. they are awesome fish. back in the early 90s they were all over the pet stores lol

now everyone knows how big they get LOL

 

[thebiggerthebetter]

I am not aware of proven pacu hybrids, which doesn't mean at all they don't exist.

Adult RB often display a darker bottom half (not always, some appear indeed just mostly grey silvery over the entire body or the bottom half is barely darker), reminiscent of the true black pacu. I don't think this this trait has anything to do with hydridization, it's in the RB genes.

I did have one RB which was almost black / very dark grey all over.

True black pacu
-- usually olive, greenish brownish top and stark black bottom
-- oval shape vs more diamond-like for RB
-- have two white fleshy, soft "fang"-like protrusions on lower lip
-- most telling different adipose shape and movement, the RB's rounded adipose flaps left and right like a lifeless appendage, while black's adipose is pointed and by comparison is muscular and used for stabilization and swimming control.

 

[Muckfish]

Interesting thanks for the inputs. There is certainly some variations since really only two display these darker colors. I am still seeking some true black pacu and perhaps then the difference between the two fish will become more apparent while looking from above.
Does anyone know if these fish can spawn naturally in a pond?

 

[thebiggerthebetter]

pacu mom

 

[johnny potatoes]

This is what a true black pacu looks like. The red bellies turning black over time doesn't help with the ID of these guys

 

[pacu mom]

pacu mom

pics from the internet




On MFK, Johnptc's black pacu





RED BELLY PACU OR BLACK PACU?
Red bellies have a more rhomboid shape. Red bellies have a more rounded head. They also have smaller adipose fins that lack rays. The adipose fin will probably look like an extension of fish skin. The fin flops around from side to side depending on which way the tail is moving and the body is moving. Black pacu have adipose fins that are supported by bony spines known as rays. So if the pacu has an adipose fin that he can move around like his dorsal fin, it is probably a black pacu. The opercula is short on the red bellies as compared with the larger semi-lunate shaped opercula on the blacks.
https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=427
Here are some pictures of black pacu:
https://www.flickr.com/photos/dave_irving/3749678082/
https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=418
http://www.seriouslyfish.com/species/colossoma-macropomum/
There is a lot of confusion about pacu. Even scientific names are confusing. Red belly pacus are the most common. They used to be called Colossoma bidens. The classification is now Piaractus brachypomum in all current literature. Another name is pirapitinga. They can get up to 3 feet in length and weigh up to 55 pounds. Juvenile red belly pacus usually have red chest and bellies. The red color usually fades, and adults resemble black pacu in coloration.
Red bellies have a second row of molars in their upper jaw, and blacks only have one row…but how many of us are going to be checking out their teeth…
Blacks have an oval shape, while red bellies are rhomboidal in shape.
http://www.acuteangling.com/.../tambaqui-pirapitinga.html
Black pacu are far less common. Their scientific name is Colossoma macropomum. They are also called Tambaqui. One article I read said they can get 3 ½ feet and weigh 97 pounds. It gets extremely confusing when searching the internet on this subject, because some of the authors themselves get mixed up and post pictures of adult red belly pacu, when writing about black pacu. The similar coloration of adult red belly pacus throws even the authors off.
Albino pacus are also Piaractus brachypomum, so are albino red bellies. I suspect the silver ones are just crosses of albino and regular run of the mill red belly. I seriously doubt that they are breeding a new type of pacu. The silver ones have the same morphology (rhomboidal shape) as all Piaractus brachypomum.

I was ignorant enough to think that I had black pacu because they were very dark. I was wrong


They are very interactive fish and very curious about the world inside and outside of their tank.

 

[Muckfish]

Great information. Thank you