Our 7+1 pacu

[moe214]

Thank you much for all these, PacuMom and Moe. I am learning.

Moe, I'd think that a rather subdued variation in the color of the belly while keeping all the looks and body structure of a red belly could mean that this common name has not a real species behind it. It also could simply stem from a difference in diet, for instance an inclusion of carrot with its load of yellow, orange, and red pigments. Or an age thing - a red belly pacu in transition from the red-bellied and red breasted juvenile coloration to the grey / silver subadult / adult.

Jeff Rapps has labelled fish wrong before, especially non-cichlds. And that's ok.

Moe, can you find a serious article / write-up / reference, scientific or popular scientific, mentioning the existence of the yellow belly and matching it with a taxonomic name?

PacuMom, I will observe closely the adipose fins on my pacu and will report back.

My initial thoughts when I first saw it was a locale variation or possible subspecies vs a whole separate species. At that time to me thinking of small pacu seemed to have SD written all over it. But after searching and reading, I found plenty of stuff as pacu mom has already shared lol. And whether we wanna accept it or not while they look similar to my eye they also look very different (SD and pacu).

And I too have noticed and even corrected jeff in emails on some of his ID's on his lists. Especially after receiving the wrong fish one time lol. However I have defended him understanding there's simply so much to know and being as busy as I think he is I can expect and accept he won't get everything right. Hell I push a lot to the side everyday to be up here let alone do specific research.

 

[pacu mom]

I had a typo--meant to write Wikipedia is NOT a scholarly site. Anyone can contribute.

 

[thebiggerthebetter]

Please do me a favor and compare the adipose fins of the blacks and red bellies. The blacks adipose fins have rays, the red bellies do not. (from the articles I have read) Can you confirm that for me? I can say that the adipose fins on my pacu look just like a skin extension and just flop around. Since you have both, you can do all the comparisons. Blacks look so different to me, since I've never seen one in person.

Sorry it has taken so long but I've not forgotten your request.

It's just not easy to see what they do with their adipose fins as it doesn't actively participate in the swimming. I found time to observe them a few times and finally became rather convinced of what you say is true. If your ID's are correct (and I believe they are), then yes, true black pacu appear to be able to move their adipose fins in a controlled manner, unlike the red-bellied pacu whose adipose just as you said flaps around with the overall body motion.

Of course, as I mentioned above, true black pacu adipose is bigger and shaped a bit differently from that of the red bellies, and given their slight functional difference, this too makes sense.

 

[pacu mom]

Thanks for the update!

 

[moe214]

I finally got to see a true black pack in person and boy the ID is as easy as it is on the internet lol. My lfs got a small one in about 8", they don't know it is a black.

 

[pacu mom]

They definitely look different from reds

 

[Deadliestviper7]

They definitely look different from reds

Once you've seen a good example of each they are easy to tell apart, well except their hybrids.

 

[pacu mom]

Since pacu breeding in captivity is done with a lot of assistance, i.e., two pituitary injections for the female and one for the male before the eggs and sperm are harvested, I guess we can assume that hybrids are manipulated by the breeder.

 

[WOLF2013]

Your pacus are very happy and healthy looking! I commend you for saving their lives and giving them a great home! I love pacu I wish there were a smaller growing species.

 

[thebiggerthebetter]

Your pacus are very happy and healthy looking! I commend you for saving their lives and giving them a great home! I love pacu I wish there were a smaller growing species.

Is it not called a silver dollar?