Cichlids are unpredictable

[Gman9272]

So my formerly sub dominant male hrp became the dominant male in their species tank maybe a month or so ago but everything was still fine they both had their territories both had their females and life was peaceful I did a water change yesterday. And today he went nuts he destroyed the other male and was attacking everything in the tank. So needless to say someone will be rehired tomorrow here’s a pic of each male the dominant male is first the second pic is the one he messed up

 

[Deadeye]

That’s cichlids for you! One day they just turn around and beat the crap out of something (maybe they’re bored?). My auratus recently decided he didn’t like being second in command to a red zebra, quickly fixed that (zebra still alive but stressed).

 

[Ogertron3000]

Thats the way it goes unfortunately. Guys like duanes are always saying it happens but for me and a lot of others you have to see it happen in your own tank before you truly understand how unpredictable they can be and how suddenly they can switch and suddenly decide to start a massacre.

 

[Gman9272]

Yea it’s crazy the tank was so peaceful and changed so quickly

 

[Man-made Monsters]

I have only had this happen twice. Both times were out of the blue and terrible. The first time a female Texas cichlid, that I had for several months in a 125 with 4 other Central American Cichlids decided in the middle of the night to go into breeding dress and pair up with a Vieja Synspilium. The two of them, mostly her, killed two of the other 3 fish that night. The second time was years later when the largest male in the tank died, he was 9 years old. Well the next male in the pecking order to step up to be the dominant male in the tank decided he was not going to be a peaceful ruler and tore apart every fin of every fish in the tank. Killing two of his five tank mates. Cichlids can change like a flip of a switch.

 

[Gourami Swami]

Yup they are unpredictable and things can change in a snap. A water change, new decor, new fish, growth in one fish, etc. can change the power dynamic in the tank. This is why most of us who have been keeping cichlids for long time advise people to err on the side of caution instead of trying to shoehorn fish into setups that *might* work. Not saying that's what you did, just a recurring theme here.
Nice looking fish by the way

 

[duanes]

To me its more odd, to have a long term peaceful cichlid community cichlid tank, than to have rampant aggression, especially if the tank is under 6 ft long.
Most medium sized mature cichlids will hold a territory of at least 4 x 4 feet in nature (upwards of 200 gallons), and they only break off chasing interlopers after a length of 4 ft, so even a 6 ft tank leaves little room to not be cornered and shredded by an dominant territorial adult.
I usually kept only a pair, in a 6 ft tank, or 1 male and multiple females, and even in those size tanks, use a divider with a hole cut that only the females could fit thru, at about the 4 ft mark. (Unless of course the cichlids are shoaling species like many Geophagines, Thorichthys, or Cribroheros, and even then, a tank under 6 ft is usually too small for a shoal)

Or if the cichlids were too similar in size, they'd spawn thru dividers

Tome a cichlid community is only a temporary grow out , situation until any one male becomes mature.
One other thing, a cichlid community with all (or even two) of the same genus, is even more precarious.
One seldom sees more of one genus in a localized area together, except maybe Thorichthys.

 

[Gman9272]

Gourami Swami duanes i believe all of us are guilty of throwing a hodgepodge of fish together at some time in our fish keeping tenure (mostly at the start). In this case this was not that it was two pairs in a 75 gallon with swordtails as dithers. They coexisted for over a year together until the one male became the absolute dominant one and went crazy. Of course hindsight being what it is this was destined to fail the tank could not support two large dominant hrp males in a breeding environment. Now I went to the lfs I had to call multiple as one didn’t want the hrp at all. and rehomed the aggressive male. Now what I believe is a little funny they put him in quarantine and of course they had a normal convict male the same size and the hrp promptly put the convict in its place which I thought would be the opposite. Also and I know I’m starting to ramble the color difference in the two was incredible I don’t understand why more people don’t keep hrp they are so beautiful and colorful compared to convicts

 

[Magnus_Bane]

Gourami Swami duanes i believe all of us are guilty of throwing a hodgepodge of fish together at some time in our fish keeping tenure (mostly at the start). In this case this was not that it was two pairs in a 75 gallon with swordtails as dithers. They coexisted for over a year together until the one male became the absolute dominant one and went crazy. Of course hindsight being what it is this was destined to fail the tank could not support two large dominant hrp males in a breeding environment. Now I went to the lfs I had to call multiple as one didn’t want the hrp at all. and rehomed the aggressive male. Now what I believe is a little funny they put him in quarantine and of course they had a normal convict male the same size and the hrp promptly put the convict in its place which I thought would be the opposite. Also and I know I’m starting to ramble the color difference in the two was incredible I don’t understand why more people don’t keep hrp they are so beautiful and colorful compared to convicts

It's mostly, imo, because convicts tend to be more durable fish in the end. Convicts can take a wicked amount of punishment and still come out just fine. Had it once where the tank stand for the 60g broke and I had to shuffle fish around into different tanks to make enough room for my FH Jr. Well in the process the convicts got booted to the now tilting 60g with a stand that could completely give out at any point. Just to make matters worse for em the tank could only be half full to prevent it from sliding off and in doing so I couldn't use a heater or filter for the tank since the water level was too low. Well this all happened just at the end of winter so the garage was still a bit chilly, bout 60°F on average or as low as 52°F on a really cold day. So yeah least to say them convicts being in there for over 2 months with no heater, no filter, no air/water circulation and only being fed once every 5 days was definitely an excessive amount of abuse on my part. Surprisingly tho I didn't lose a single one at all, 5 went in and 5 came back out. No body was thin, they were all fully colored (atleast they didn't look stressed), there was a few tattered fins on the smaller ones but I expected that, but over all everybody turned out fine. It wasn't untill they had settled into their old tank, after I got Jr's tank moved and set back up, that they decided to kill each other. The last 2 were the most dominant females and they just literally killed each other within only 1min of starting their fight, just ripped each other gills out. Only survivor I had was the male at the end of the day and that was just because he went to a separate tank from the females at the start. He lived on for a few more years afterwards, he just passed away a couple months ago at a lil over 5 years old and 5in long. His name was Lokir and I got him at ¼in for $0.25 from Petco lol. Meanest fish I've ever kept.