Dominant Boesemani Killing Other Males

HI there!

As the title suggests, I'm having trouble with the largest of my BoesemanI Rainbows. He is gorgeous, but he's territorial with other males and has now killed 3 of them.

I had a school of 4 males and 3 females. I went out of town for a few days, and came back to find 2 of the males gone. I could only assume the largest male killed them and they were eaten, as they could not have jumped out, and the only other inhabitants were a clown plecostomus and a 5 year old very docile rainbow cichlid. The 2 remaining males were seemingly the oldest and the youngest.

Now several months later, as the smaller male has colored up a bit, I've been noticing more aggression again. My plan was to buy one more pair to bring the school up to 3m, 4f, but I've not found any locally lately. But yesterday I found the less mature male all beat up, fins ripped and not acting well. By last night he was swimming vertically, flipping upside down and floating, and wedging himself against the heater or plants. This morning he died.

So I'm unsure of what to do. Should I stick with my plan and now get 2 more males and another female? Or would a different ratio be better? I'd be bummed to have to leave him as the only male, as he's gotten so beautiful and Id love to have more, but I don't want to send more guys in just to be terrorized.

What would you do? Does anyone have a tried and true ratio?

My tank info: Cycled and running since 2011. 50 gallons, 48 inches long, Eheim 2217 canister filter, sand, driftwood, real plants (just added), 77 degrees, nitrates around 30-40 (have not tested ammonia and nitrites in a while but will tonight), inhabited by 4 BoesemanI Rainbows (1m, 3f), 1 Rainbow Cichlid, 1 Clown Pleco, and 3 Nerite snails. I did have an issue with my heater 2 days ago, so there was temp fluctuation yesterday and the day before (up to 82, down to 70, then back to normal over 2 days). That is the only issue the tank has had recently; in fact it is cleaner now than it has been in months.

 

You need to have far more females than males in the tank. Something like 3+ females per male. They don't pair up and are unwilling to share their females so fighting over the few females available is to be expected.

 

I ended up with only one male. I kept my shoal in my 6' 110g tank and they spawned every single morning. I raised fry too.

My strain was very big indeed and all smaller tetras etc. were seen as tasty snacks.

 

You need to have far more females than males in the tank. Something like 3+ females per male. They don't pair up and are unwilling to share their females so fighting over the few females available is to be expected.

I knew the original 4m/3f ratio wasn't good, but the LFS owner convinced me "they aren't like livebearers and it doesn't matter that much."

So I should either stick to just one male, or increase the school to 8 and do 2m/6f then.

I ended up with only one male. I kept my shoal in my 6' 110g tank and they spawned every single morning. I raised fry too.

My strain was very big indeed and all smaller tetras etc. were seen as tasty snacks.

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Gorgeous! Those look like all males. How big of a school did you/do you have?

 

I would have one male from the start because you may have only one male at the finish. Plus I'd have 3 or 4 females to spread out the male's attention as he will tire the females out.

I believe I had equal numbers of males and females initially about 8 of each. I was given some fry by a very special breeder so had about 45 fish initially and sold some as they grew. The fry were slow growing but very healthy and reliable with no deaths.

I sold my Boeseman's because after seven years I decided they were not for me. I prefer Congo Tetras. The Rainbows are too vigorous for my taste.

 

I would have one male from the start because you may have only one male at the finish. Plus I'd have 3 or 4 females to spread out the male's attention as he will tire the females out.

I believe I had equal numbers of males and females initially about 8 of each. I was given some fry by a very special breeder so had about 45 fish initially and sold some as they grew. The fry were slow growing but very healthy and reliable with no deaths.

I sold my Boeseman's because after seven years I decided they were not for me. I prefer Congo Tetras. The Rainbows are too vigorous for my taste.

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Beautiful tank and fish! I wish I had the space for something a little bigger.

I've been reading a lot about rainbows and some people say the aggression is much better when there is a bigger school with at least 3 males. Do you think there is any truth to this? I'm either going to stick to 1m 5f, or go up to 3m 6f, I think. My tank also needs more hiding places currently, as I recently took out all the plastic plants and fake looking decor, and am slowly adding live plants, so that's something that will be addressed.

 

I had eight males and ended up with one.

I'm just saying what I found not what anybody else found.

 

I breed boesmani, and get very close to 50/50 sex ratios. So I find that keeping 15, with 5 to 7 males eliminates aggression. But that is in a 4 foot tank. They need space. May males display and spar a bit, but no one gets hurt.
When I can first sex them, I sell off the older males and move out a few pairs. I keep breeding them not for money, but because I have the bright orange wild sourced line, and if I ever lose them, I'll never find any as colourful again.

 

I breed boesmani, and get very close to 50/50 sex ratios. So I find that keeping 15, with 5 to 7 males eliminates aggression. But that is in a 4 foot tank. They need space. May males display and spar a bit, but no one gets hurt.
When I can first sex them, I sell off the older males and move out a few pairs. I keep breeding them not for money, but because I have the bright orange wild sourced line, and if I ever lose them, I'll never find any as colourful again.
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That's what my one male looks like, but none of the others ever got that colorful, or as large (I guess they didn't get a chance to). My tank is 4 feet, but I also plan to have 2 dwarf cichlids, a clown Pleco, and a school of cories, so I think 9 is the biggest I would go with my rainbow school.

 

Would Rainbows coexist with cardinal and Congo Tetras.

 

My adults would eat Cardinals but they were huge.

 

I bought 2 pairs today. Well, I hope they are 2 of each sex. They are so, so, small compared to my other 4! One is starting to show male colors, the rest are a toss up. I had planned to get 3 females and 2 males today, but they didn't get that many in and they aren't really sexable anyway, not to mention expensive! I'm keeping my fingers crossed for these little ones, that the big guy doesn't bother them (they are still acclimating in the bag). If I see a lot of aggression, I'll rehome all but one male. If not, I'll add one more female as planned.

 

They all seemed great at first. The little ones were schooling with the adults, and the adults completely ignored the babies. The only aggression I saw was between the babies. Tonight, I found one dead with its mouth wide open at the bottom of the tank! Another one has a small tear in one of its fins. I don't understand what is going on.

 

Well you just validated my concerns. We have 2 boesamanI in my 55 gal and the male is full size and is a beast lol though he is friendly and gets along with the other fish in our tank. When we got them we didn't know they were happiest in a school though my 2 are happy beautiful colored fish. We bought 5 juvenile (3 female and 2 male) and they are tiny. We put them in a different tank to give them time to grow before we put them in the big tank with the adult pair. I am concerned about when we do move them. Will they mesh? Will the big one bully the other males? Or how big I should let the lil ones get first? I was concerned about the adult maybe being aggressive towards them since they have been alone in their...so your thread validates that. Now I may need to start a thread to find out best way and when I should move them over.