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Breeding Pygocentrus nattereri

(As told to members of Piranha Fury, March 9, 2003 to present)

Photos and Text by JOHN KLOHN  (Editing by Frank Magallanes, OPEFE)







I have six red belly piranhas in a 125 gallon. The smallest being roughly 4 inches and the largest in between 6-7 inches. The two I saw mating were the two biggest. These two were from a separate batch so I got pretty lucky. There has been one piranha guarding the eggs ever since I seen them spawning he/she will not let anybody around she just keeps spinning around and around and once and awhile he/she scoops down over top like when they are itchy but doesn't touch the rocks I was noticing.This all started on sat night after gravel cleaning and water change. I was told by my local fish store that's what they do. They wait till you clean the rocks and water change so that they know you will not harm the eggs. I guess they must know that water changes don't happen everyday. And they have enough time before next cleaning. 


Well it doesn't look too successful my first time with spawning. The eggs look like they are almost gone and no fry to be seen. I have made some changes to the tank; I have cleared some gravel and placed a flat rock at the bottom. Hopefully they will use the rock for the eggs next time. I have also turned the temp up to 83F degrees it was at 80F degrees before. The piranha is still in the same spot doing the same circles but can't see the eggs like before. I'm hoping they know something I don't. I have the 10 gallon tank ready stable at 82F degrees and I will keep on trying. I will let everyone at p-fury know how the progress is doing as soon as I see more eggs. 


It didn't take to long for my piranhas to get to know each other! They have only been together for 10 days and already I have eggs. One of them is guarding them spinning in circles well the other one is not to far away. I seen them in action last night, so today i looked in the tank and yes little yellow eggs now. I don't know anything about small fry fish but I have a 10 gallon aquarium empty. I just cleaned it out and put it away last weekend. Well time to put it up again. 


Round two just seen them pair off again hope this one works out. I did not see them do the wango tango yet but they are protecting a specific area in the corner of my tank. The thing I don't like is it is very close to my power head 901.My concerns are if there are eggs now or soon does this mean i can't use my power head will they get sucked up or do they stick good to the rocks? Well getting very close now the eggs are now hatching and there is movement going on. The papa piranha is protecting his investment with great pride, i hope they pull it off. I need to get that power head back on fast i am only running a Rena Filstar XP3 pushing 350 gph. I also have a 12'' air stone but this is a 125 gal. tank and I need that power head back on. 




Here we go this time. I didn't see them do the mating dance but I noticed they moved over to the far side of the tank away from all the other piranhas so it was like right on! Three weeks went by here we go the next morning. I noticed the male, because he guarded the eggs last time. They are both the two biggest in the tank, the male is a little bit smaller in length and a lot skinnier. The female ballooned out, she has a lot of darker coloring and nice purple spots where he has always been very light in color and didn't change to much. 


He is one angry piranha I hope he doesn't freak too much. I have never seen him spin in circles like a tornado before and then he bolts out to the middle only to go right back. He will make eye contact with me and watch me facing head on. I am leaving the eggs in this time around as I feel they are safer in there then in the 10 gal. I have prepared a sponge filter in there soaking since last time, in the old water from the host tank. I will siphon out all the water and fill it with some new water from the host tank. I had read some info on another web site and that person recommends leaving the fry for a week or two with the parents. But I'm not sure if they would last that long as i have six piranhas in there. 


I have kept the water temp at a steady 82 deg my water change was due on Saturday. I did not do one because I figured to much stress on the papa piranha. I have been overfeeding them to keep them full. I noticed the mother piranha eating like a pig! She deserves it good job mama piranha. I have not put the lights on since Saturday night and stay away as much as possible my water parameters are fine checked this morning. 


FEEDING TIME (Fry and Adults)


I don't know much about that brine shrimp. I seen it frozen in little cubes but they also sell little kits with some pouches to make your own. I thought they sold freshly made ones already but i guess not. I think I'll try those Hikari special fry flakes which sounds easier to use. I just threw in four little neon tetras. At feeding time I usually always feed by opening the middle lid of the tank. I throw in just enough that all six could get a little bit to snack on. But by far the female is the most aggressive piranha in the tank. I swear she will snatch more shrimp in her mouth than all the other five. She must really work up a appetite and not to mention her size. I checked again this morning, and decided to do a siphon. I first had checked the water parameters in the 10 gal and it was pretty high with nitrite and nitrate due to adding those tetras. so i did 4 partial water changes with the water from the host tank until I had a good reading, don't know if that will do. But, it's done then I started to siphon out the small fry. I did not go crazy and try to get all of them as I took out maybe a hundred or so as I looked in the pail. I noticed lots were swimming and a few were not. I had poured the water in very slowly and five minutes later I checked to see if I could see any movement in there. I was happy to see some swimming freely. 


I noticed some on top of the sponge filter and some on the decorations. I will watch the progress over the next 24 hrs and decide if I should siphon more of them out.


Today, I checked the fry tank out and wow nothing moving. All the fry looks to be dead checked water parameters and wow!!! Now I know why no fry. Cycling is in high gear some ammonia signs very high nitrite, and maximum nitrate. So I even threw in more gravel and decorations that should help. Even more tetras still alive and to boot the temp went up to 84F+ degrees. Not a problem because the host tank has 200 plus free swimming babies. And no signs of parents gobbling them up yet. I am making some newly hatched brine shrimp and feeding small crushed flakes going back to LFS today to pick up some of those Hikari fry flakes. But the father in the tank guards all the eggs and fry but when he gets some food he will not eat it. He kind of just seems to chew it up, and play with it. At first it never dawned on me what he was doing. But after awhile finding pieces of food in some very weird places. I watched him a little closer and noticed he was saving for the small fry most likely. but the pappa fish doesn't realize that I can not let this happen. As he makes me have high ammonia readings this way.


Here is a picture of the mother piranha after eating, 5 days after spawning? Oh and right now i have 6 adult piranhas - 8 (7 week old) and 13 ( 3 week olds) and my last batch, by far my best batch has over a 150 fry still living. I had done some tweaking to my normal routine and so far much success. At this period in time I was pulling dead ones out by 25-50 daily. But I have only seen one dead so far!! I'm expecting to lose some more. 



Here is the father piranha guarding a frozen silverside minnow. He bit the head off so the fry could eat on the insides. I'm not positive but he would always saves a portion of some food and guards it.  I don't know if the fry would eat it, as i always removed the old food.


Male guarding food.


Close up of cut minnow.

A baby piranha pooping


When I siphon eggs, I don't take them all out. This is a picture of the ones that were left behind that hatched and are swimming around a few days after. They are about 4 days old at this stage. They seem to lay low at first not swimming around. Their swimming skills are very poor at this stage. They tend to all fight for the corner of the glass, and almost stick on it like a Plecostomus species. They can't idle in one spot, they move or will sink. When they want to descend they just drop straight down like a plane crashing, then a couple seconds later they will move. They lie down on their sides on the bottom not moving till a snail or something spooks them then they will dart off. 


Here is a picture of them chillin.

2 weeks old

One month old


On Saturday, I had to do a routine water change and gravel clean, so come Sunday i decided to check my parameters to make sure if everything was alright. The ammonia was a little high, but no signs of nitrite. I figured it would be ok, but\did some small water changes to help dilute, and bring down the ammonia a little. I  knew it would probably have a delay in breeding from past experience. Whenever i do something to the tank outside of regular water changes that it causes a delay in breeding. But right now, I don't have any room for more fry right so I was willing to proceed anyway.



2 weeks

3 weeks

30 days

4 weeks

5 weeks

6 weeks

7 week

Fry holding Tank


Sexual dimorphism; Male? or Female?


The male piranha was in the nest the whole time, doing his thing. But the female was no where near him. She remained at the other end of the aquarium, and did not go by him at all. Today being Thursday, I was starting to wonder if maybe this was the end of the breeding. But around 2:30 pm I noticed that all the piranhas were swimming around and looked spooked. Shortly after they were starting to fight with each other. The male was scraping with another piranhas. I shined a light on them but they did not stop fighting. I had to leave because needing to be somewhere else at this time and I thought that they would have it all settled down by the time I returned. When I returned in around 6:30 I looked in and they were all spread out and quiet. I looked at the nest and the piranha in the nest was not the male or the female there was another piranha who had taken over the nest! Now I don't know if this is a male or a female piranha in this new nest! But the female is beside this piranha. I figured that the female dumped the male for a new piranha. The male was over in the middle, but looked ok. His fins did not look damaged and he was not hurt. So now was there going to be no more spawning? or do i have another male who wants to breed with this piranha? Or will the known female try and play them both?


Breeding in new location


So I left them alone for a bit and came back, still nothing then checked again later to see the female back with the original male. They were side by side in the middle of the tank. Then a half hour later I seen them starting to breed again. But they were not in the nest. But big deal, I was just happy to see that they still can breed.


Every so often in between the mating ritual with this female, he kept going back to the nest to start to fight with the other piranha in that nest. So they did their thing till 1:00 am and then the piranha in the nest had taken off back to the other side. The piranha, which I thought was a male and now turns out to be a female now ends up going back to the nest and starts digging and picking rocks. So now the male is in the middle guarding eggs I presume and now the female is digging a nest. So what happens now? 


1) the female is digging for the original male to come back and leave his eggs.?
2) the female is going to bang them both?
3) she will just control the nest for future eggs?



(L) Female beat up a little.

Being measured approximately at 6 inches TL.


I stuck a meter stick outside the glass on the stand ledge (SEE ABOVE). I know this does not give an accurate measurement, but it shows that she is probably around 6 inches or a touch larger maybe. She was about 1.5 inches back from the glass in photo above.




KLOHN, John 2003, Breeding Pygocentrus nattereri, Piranha-Fury web site.






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