# Controlled Rhom Co-hab



## BRUNER247 (Jun 2, 2010)

Has anyone considered or tried a controlled co-hab with rhoms or other solitary piranha? He's my thoughts, references say most of the more aggressive piranha are solitary or loose shoals, except when they come together to breed.I have a 8'x4' tank I plan to divide it into 4- 4'x2' tanks with a common corner in the center.sooner or later 2 are gonna show some signs of wanting to spawn. Anyone else try anything like this? I got this idea from JP80911 after watching his you-tube video of 2 rhoms in a split tank.looks to me they begging to spawn! So I thinking 4 fish per tank to up the odds even more, plus more fish could easily be on standby in other tanks.plus if enough fish are available n 2 pairs are formed the tank split in 4 could be made into 2-8'x2' tanks as there is thought that hormones can trigger other pairs(I swear I've witnessed this with my rbps!) to breed also. What's everyone else think about this idea? Anyone experienced wanna grow a rhom or two out for 2 years so we can put this to the test?


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## JoeDizzleMPLS (Nov 5, 2007)

Don't worry about the double-post, I deleted the other one...









If I remember correctly, JP's rhoms were REALLY trying to get at each other, most rhoms that I've seen in divided tanks spent almost all of their time trying to get through the divider to get at the other fish and I really don't think they had intentions of breeding, they just wanted to kill the other fish.

If I were to put together a serious attempt at breeding rhoms, I would most likely start out with a large group of baby rhoms in a huge tank with lots of places to hide, then I'd keep an eye on the tank and remove the biggest aggressors in an attempt to narrow it down to a handful of fish that seem to be a bit more tolerant of tankmates. It would be a very long process, but I think I'd rather put in the time than taking two larger expensive rhoms and dropping them into a tank, that could be a lot of money down the drain within a matter of minutes.

Who knows, I may end up with one fish in either situation, but I think that's the route I'd go with.


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## BRUNER247 (Jun 2, 2010)

Idk I disagree I just watched it a few times a couple nights ago.they both were at the divider but it was all nice slow swimming, it even shows a lot of tail twitching.personally I never seen any what I would perceive as wanting to kill each other. That's why I say raise 4 in same tank they'd be used to them being near already when n if they showed any signs of wanting to breed. I also think with the higher aggressive piranha the spawning is surely more aggressive also so maybe what some perceive as wanting to eat each other, others see a pre-spawn behavior? Ill see if I can get JP to post the link.


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## jp80911 (Apr 3, 2008)

Here are some of the videos I recorded with my IP camera when no one was around the tank.


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## BRUNER247 (Jun 2, 2010)

Thanks JP your the man! I can't see it unfortunately, as I'd love to watch it a dozen more times.but I know what I saw! JP what's your take on the video.plus they were your fish, am I way off base?with what you know now n watch that video n thinking back.do you think it might have been possible? Thanks again JP.awesome fish! Including your present rhom! He's a stunner!


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## jp80911 (Apr 3, 2008)

The reason I decided to put these two rhoms in a divided tank was one of them (the smaller one on the right, ~7.5" at the time)had a bulging tummy at the time which wasn't there before. and I know it wasn't from feeding so I thought those might be eggs. the only other sexually matured rhom I had at that time was the one on the left (~9") so I decided to give it a try and hoping for a pair.
They basically mind their own business when they do not see each other (I had few piece driftwoods near the divider on both side so they don't see each other all the time) and only tried to swim towards each other when they are in sight of each other. sometimes they follow each other swimming back and forth along the divider sometimes they just went head to head and sometimes kind like dancing a bit like tail twitching, can pretty much see all of those in the videos I posted. nothing really extremely aggressive from what I've seen...unlike one of the videos I saw on youtube a while back with two large size black rhoms in a 125 or a 180g with a glass divider, one freaked out and tried to get over the glass divider and splashed tons of water and sand out of the tank....just couldn't find that link now.
I didn't spend a lot of time in front of the tank other than during feeding because I do not want to get in the way of their possible romance, most of the time I just watch them over the IP camera. 
I could probably find out exactly how they felt about each other if I had the guts to remove the divider but I didn't....I know I was a wuss but I didn't want neither of them get hurt.


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## BRUNER247 (Jun 2, 2010)

Cool thanks JP. The way I see it is if they were wanting to eat each other they'd have been mouth to the plexy going off.like you said bout the other video from someone else.n even not quite to that degree of tryn to jump the plexy ect. But what I see in JP video is a possible pair.its still a guess either way.but I see two fish that are exposing their sides to the other one.even if there is a divider there. Only time I see one really mouthing with any real energy is when the fish on other side is away from the divider.which I'm aware even a breeding pair can n will kill each other.hell even some oscars will kill a mate!its nature way of passing the strong genes. Only the strong survive! I've seen a couple really nasty fights between my oscar pair.I'm constantly having to step in n make em quit! N I don't blame ya none JP it woulda been a gamble without the divider! I think the divider n keeping a close eye on em n wait for the signs then combine them.idk time will tell! I'm a gambling man!I'm gonna roll the dice!


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## JoeDizzleMPLS (Nov 5, 2007)

I hadn't seen those videos before, but I sure as hell wouldn't have removed that divider. I will say that they weren't going nuts the whole time trying to bite through the divider, but I had a couple rhoms in a temporary divided tank once that seemed to be just fine, never bit at the divider, but were constantly swimming back and forth trying to check each other out, one morning I went to check my tanks and the larger rhom had knocked the divider loose a bit just enough to squeeze through and there he was chillin with a floating head at the top of the tank.

Rhoms are very territorial and unpredictable, so it's gonna be a tough task getting them to breed, someone who is serious about it will most likely end up going through a lot of money and quite a few specimens before they have success. It may take a lot of fish before you can find two that are willing to start the breeding process and then the danger of one killing the other will be just as high again so you could lose one of your potential breeding pair and then have to start the entire match-making process all over again.


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## primetime3wise (Sep 28, 2003)

the other huge problem anyone is going to have, besides the fish tolerating each other enough, is getting them into the mood. most likely, just tossing a male and a female in a tank together, and having them be ok with one another, isn't going to be enough. far from it. this seems to be the problem with breeding any piranhas other than p. nattereri and s. maculatus. otherwise, plenty of people would have bred terns, caribe, piraya, and a few others. the typical way of getting them into the mood is simulating the wet/dry seasons in the best possible way, and even then...

and as far as i know, as long as i have been here no one has even seen any pre-spawning behavior with s. rhombeus. someone on MFK a while back had a female lay eggs, but the fish was by itself.


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## BRUNER247 (Jun 2, 2010)

I know its a gamble.3 of the know breedings of rhoms they didn't try to replicate the rainy season.Germany,Vegas, & I believe shed aquarium, correct me if I'm wrong.nothing special was done other than a huge tank, n proper care.I know the Germany tank ultimately ended with 1 remaining fish, the other two might of also idk, I would love to hear what ending up happening with these. The piranha that have been bred in tanks all pretty much show the same signs at spawning time, some more aggressive than others.which can lead to tragedy at any point.I thinkn some in same tank, can't kill each other, used to seeing each other, would/could possibly lead to showing a spawning sign.which even with a strong spawning signals it could still lead to tragedy. Example my male oscar flipped out last night killed his mate & 14" pleco.they had been cleaning a slate heavily for last two days.it was going to be the last time I spawned them as the first time they were very aggressive with each other.I just thinking of a possible way to up the odds a little with the more aggressive piranha n not just rhoms.think about this same tank idea with caribe or spilos. Maybe 4-6 in each section. Idk guess I'm just crazy like the other forums say.the proof is there for all to see that everyone putting too much stock into wet/Dry season,ect. If you can co-hab and give proper care sooner or later they could pair off n breed.what better way than a split tank?can't kill each other at least till you join them.other fish it helps to split them till breeding.they are mostly solitary fish.


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## Grosse Gurke (Jan 3, 2003)

I have kept a few aggressive species together and it isnt like they just tear into each other....there is a feeling out period. You generally dont see two boxers run to the middle of the ring and start swinging because their opponent has the ability to take them out as well. There is a lot of posturing in the fish world...and that is more what I saw in those videos. The tail twitching can also be related to aggression...or defense posturing. If you see how these fish hunt...it is always from behind...take out the tail and the other fish is helpless. When fish are feeling each other out....IMO....there is rapid movement of the tail to protect it from being damaged.


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## primetime3wise (Sep 28, 2003)

Grosse Gurke said:


> I have kept a few aggressive species together and it isnt like they just tear into each other....there is a feeling out period. You generally dont see two boxers run to the middle of the ring and start swinging because their opponent has the ability to take them out as well. There is a lot of posturing in the fish world...and that is more what I saw in those videos. The tail twitching can also be related to aggression...or defense posturing. If you see how these fish hunt...it is always from behind...take out the tail and the other fish is helpless. When fish are feeling each other out....IMO....there is rapid movement of the tail to protect it from being damaged.


i agree with this. i didn't really see anything in jp's videos that would indicate prespawning, or an inclination to want to spawn. more just how 2 rhoms would normally act in a divided tank like that.


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