Social dynamics in semi-aggressive fish

Discussion in 'Advanced Freshwater Aquarium Topics' started by Dempsey Dude, Aug 4, 2015.

  1. Dempsey Dude

    Dempsey DudeWell Known MemberMember

    Keepers of medium sized to larger cichlids will probably appreciate the phenomenon I'm about to describe: it's amazing how the entire dynamic of a tank full of semi-aggressive cichlids and oddballs can change when you remove one perpetrator or bully fish from the environment.

    I had recently bought a new cuban cichlid and added it to my 55 gallon CA cichlid tank, and he almost immediately happily inserted himself into the number two position of the tank's dominance hierarchy, essentially throwing the tank into disarray. While my big electric blue Dempsey who has always been the tank boss retained his original position, everyone else in the tank became a lot more fearful, skittish, and generally uneasy from stress.

    My salvini moved into the cave that was heretofore occupied by my big male electric blue and my small female regular dempseys (who surprisingly tolerated her presence). My firemouth who recently got over a bout of camallanus worms was pushed out of his spot under the driftwood on the left side of the tank, and would just kind of hang out in the open water on the right side of the tank, which he had never done before. My convict was edgier cause the firemouth was impinging on her territory in the back right corner. The catfish who had always hung out in the back left of the tank were now sequestered to the middle and right ends of the tank. Basically this one 3.5 inch fish had taken over 2 square feet of tank space and threw everything into chaos.

    Today I traded him in at my LFS because he is one of the most aggressive fish I've ever owned. Less than an hour after his removal from the tank everything has gone back to just about normal. The other fish have begun to re-establish their original territories, and most of them are swimming out and about. Has anyone else experienced a similar situation with one of their tanks?
  2. Thai Aquarium owner

    Thai Aquarium ownerWell Known MemberMember

    Everything will appear " normal " for a short period of time. However, there will be a series of " scuffles " between the various fish to again establish an Alpha male with total tank dominance.
  3. BDpups

    BDpupsWell Known MemberMember

    Yeah I know what you are talking about. The tank you had it in is kinda small for the stock you have. But you can do the same thing with American cichlids that you can with Africans. Over stock the tank to spread out aggression. The problem is, you need a really big tank. If you had yours in a bigger tank, 180 or bigger, you could have added a few more, and probably gotten the same results.

    I know a girl with a 150 and around 10 red devils in it. She got them all at once so they grew up together too. There is a huge dominant male. The rest of the males have stayed much smaller in size, and keep to themselves. The dominant female is normal size and when spawning, beats up on the dominant male. The other females are a bit on the small side and keep to themselves with the sub males. It's a fun active tank to watch. Very interesting behavior.

    But in your case, it makes sense that when the bad apple left the tank, the rest calmed down.
  4. OP
    Dempsey Dude

    Dempsey DudeWell Known MemberMember

    Yeah the tank they are in now is definitely not gonna be their permanent home. They are still juveniles and I am growing them out. I plan on getting a 100 or a 150 for them eventually. But even in this tank, without certain aggressors, they are remarkably mellow. Very little aggression aside from the occasional short chase or nip.
  5. hampalong

    hampalongWell Known MemberMember

    Cubans are in a different league to all your other cichlids. Mixing cichlids is a bit like playing with fire. You have a tank full of matches. A Cuban is a burning fuel tanker. They grow 18"+ and take no prisoners. One of the meanest cichlids, they invariably end up alone, for good reason. You'll need a far bigger tank for one.

    It's a life or death struggle whenever you add a new cichlid to a mixed group. We just see dominance changing, but they're real fights that are happening, and the only reason someone doesn't get killed is because one has always had the sense to know when it's beaten, and back down. You said in the title "semi-aggressive" cichlids. Cubans are not semi aggressive, they're ruthless killers in the confines of a tank. you can't mix n match with the very agressive ones, especially in a small tank.

  6. OP
    Dempsey Dude

    Dempsey DudeWell Known MemberMember

    Really? My research made it seem like a cuban was basically a smaller, less aggressive version of the jaguar. Most of the websites I went to said they don't get bigger than 10". Anyway, he's gone now, and I'm happy my other fish are no longer in danger.
  7. chromedome52

    chromedome52Fishlore VIPMember

    Hampalong is correct. I have seen male Cubans at Cichlid shows that were 15"-18", with one possibly even larger. And anyone who has actually kept Nandopsis tetracanthus will tell you just how aggressive they can be.
  8. OP
    Dempsey Dude

    Dempsey DudeWell Known MemberMember

    The scars on my other fish are a testament to that! I guess most all guapotes are monsters, then.
  9. hampalong

    hampalongWell Known MemberMember

    Some more than others. Cubans, Haitians, dovii... these make the others look quite peaceful IME.