Welcome to Our Community

Wanting to join the rest of our members? Feel free to sign up today.

Why do my cardinals seem to fight?

Discussion in 'New to the Hobby Questions and Answers' started by BettaMan2000, Nov 14, 2017.

  1. BettaMan2000

    BettaMan2000 Fish Fanatic

    Joined:
    Oct 9, 2017
    Messages:
    154
    Likes Received:
    4
    Ive got 5 cardinal tetras (6 originally one died) one of them, surprisingly the smallest and thinnest is always attacking the largest that seems to be the most docile too?

    Is there a reason for this and anyway to stop it?

    They’re currently in a 54 litre long tank.

     
  2. Byron

    Byron Member

    Joined:
    Feb 25, 2009
    Messages:
    5,947
    Likes Received:
    793
    Location:
    CA
    What exactly is the "attacking?" Characins live in huge groups, and they do interact. I would get a few more, up to 8-9. I know the tank is 54 liters (15 gallons) and the dimensions from the other threads, but having a larger group will benefit the fish which in return has less impact on the tank's biological system.
     
    • Informative Informative x 1
  3. BettaMan2000

    BettaMan2000 Fish Fanatic

    Joined:
    Oct 9, 2017
    Messages:
    154
    Likes Received:
    4
    one of the fish seems to have gone rogue (its the smallest and thinnest) and really hits the largest, headbutting and chasing it on to the otherside of the tank often.

    Why would more fish have less impact on the tanks biological systems?
     
  4. BettaMan2000

    BettaMan2000 Fish Fanatic

    Joined:
    Oct 9, 2017
    Messages:
    154
    Likes Received:
    4
    Hi Byron, I'm still very new to this, I just wanted to ask why more fish would have less impact on the tanks biological systems?
     
  5. Byron

    Byron Member

    Joined:
    Feb 25, 2009
    Messages:
    5,947
    Likes Received:
    793
    Location:
    CA
    I've posted about this several times in the past, because it is something many fail to understand. I'm useless at finding old threads, so will summarize here for you and others. Some is cut and pasted from an article I wrote a few years back.

    Each species of freshwater fish has evolved to function best in a very specific environment. The "function" refers to the homeostasis. Homeostasis is defined as “the tendency of an organism or a cell to regulate its internal conditions, usually by a system of feedback controls, so as to stabilize health and functioning, regardless of the outside changing conditions.” Physiological homeostasis, or physical equilibrium, is the internal process animals use to maintain their health and life: “the complex chain of internal chemical reactions that keep the pH of its blood steady, its tissues fed, and the immune system functioning” (Muha, 2006).

    We need to understand what "very specific environment" means too. This includes the water parameters (hardness, pH, temperature); the physical surroundings (type of substrate, rock, wood, plants, light intensity, water current); the number of fish in the species (extremely important for a shoaling species); other species within the area, which becomes very important in the confines of any aquarium; and with respect to thee aquarium, the actual physical space itself. All of these factors have an impact on individual fish. This is why community tanks can be challenging...every species added has to "fit in" with all the others with respect to all of these factors.

    This greater dependence upon their surrounding environment is why fish are more susceptible to stress than many other animals (Wedemeyer, 1996). All of the above "expectations" or "needs" are programmed into the DNA of each species. We cannot change it; only evolution and nature can do that, and it takes hundreds to thousands of years. Dr. Paul Loiselle (an acknowledged authority in ichthyology and this hobby) sums it up in the green citation in my signature block. This must absolutely never be forgotten if we want healthy fish, because it is at the core of their health.

    Stress attacks the immune system and the homeostasis of the fish. If any of the above factors is missing, the fish will experience stress because of it, always. Stress is the direct cause of 95% of all fish disease in an aquarium. That is pretty significant. Various pathogens may be present, but it is the stress that weakens the fish and they then succumb to the disease.

    Stress is caused by placing a fish in a situation which is beyond its normal level of tolerance (Francis-Floyd, 1990). Stress makes it more difficult for the fish to regulate the normal day-to-day physiological functions—the homeostasis—that are essential to its life. When fish are under stress from any of the above factors being missing or inappropriate, their impact on the biological system is increased. The effects of stress on fish are very complicated physiologically, and are often subtle. There may or may not be external signs discernible to us—it can continue for weeks and even months, sometimes up to the point when the fish just suddenly dies. The reasons for this are involved.

    Adrenaline released during the stress response increases blood flow to the gills to provide for the increased oxygen demands of stress. The release of adrenaline into the blood stream elevates the heart rate, blood flow and blood pressure. This increases the volume of blood in vessels contained within the gills, increasing the surface area of the gills to help the fish absorb more oxygen from the water. The elevated blood flow allows increased oxygen uptake for respiration but also increases the permeability of the gills to water and ions. This is what is known as the osmorespiratory compromise (Folmar & Dickhoff, 1980; Mazeaud et al., 1977). In freshwater fish, this increases water influx and ion losses. This is more critical in small fish than larger due to the gill surface to body mass ratio (Bartelme, 2004).

    I've tried to explain this but there is much more to the story. Hopefully this helps.
     
    • Informative Informative x 1
  6. Demeter32

    Demeter32 Member

    Joined:
    Aug 11, 2014
    Messages:
    896
    Likes Received:
    431
    Location:
    US
    Cardinals live in groups of hundreds, even thousands in the wild. They feel safer = less stressed in larger groups.

    When you do not have enough individuals to allow the fish to feel safe they will become aggressive and attack their fellow group members. Up their numbers as Byron has suggested.
     
    • Informative Informative x 1
  7. BettaMan2000

    BettaMan2000 Fish Fanatic

    Joined:
    Oct 9, 2017
    Messages:
    154
    Likes Received:
    4
    I understand they’d feel less stressed in terms of numbers, but more fish in a smaller area than their natural habitat, doesn’t that mean more stress, more competition for food and territory?

    Besides I don’t mean to be pedantic or rude, not my intention, but you did say “tanks biological system”.
     
  8. Byron

    Byron Member

    Joined:
    Feb 25, 2009
    Messages:
    5,947
    Likes Received:
    793
    Location:
    CA
    No, not exactly. It depends upon the species. In very general terms, with a shoaling species like cardinal tetras, the more there are the more "relaxed" they will be. And the more relaxed, the less stress, and thus the less impact on the biology. Think of it in human terms--people who are under stress have a far greater impact on everyone around them. With fish it is amplified because the fish are reacting by various biological processes, all impacting the environment. The natural biological impact of a fish as a fish without any other influences (very artificial, as this never occurs in nature or the aquarium) will obviously be a matter of body mass to water volume in abstract terms. But this is not how fish "live," and their day to day "living" has impacts.
     
    #8 Byron, Nov 15, 2017
    Last edited: Nov 15, 2017
  9. NickAu

    NickAu Member

    Joined:
    Jan 14, 2015
    Messages:
    3,315
    Likes Received:
    922
    Location:
    AU
    You would think so but no not really, With shoaling fish it really is a case of the more the merrier.

    Slightly off topic.

    This is a happy bunch of Kuhli Loaches they are " programed " to live like this.

    Image not my work
    [​IMG]


    I have 15 in a 2 foot tank.
     
  10. Demeter32

    Demeter32 Member

    Joined:
    Aug 11, 2014
    Messages:
    896
    Likes Received:
    431
    Location:
    US
    Shoaling species shouldn't really be claiming territories in the first place. As a group they should act as one, much like sheep following each other.

    "Less is more" does not apply to all species of fish. African cichlids, danios, barbs, tetras, corydoras, loaches work on the basis of "more is more". The more individuals you have the more comfortable the fish will be. In a 15gal with no other fish I'd aim for 10 or so.
     
    • Informative Informative x 1
  11. NickAu

    NickAu Member

    Joined:
    Jan 14, 2015
    Messages:
    3,315
    Likes Received:
    922
    Location:
    AU
    I read some place that keeping the harder to breed small shoaling fish in larger numbers ( tank size permitting ) increases the chances the fish spawning in your tank.

    Males will display more trying to look their best in front of the girls that sort of thing.
     
  12. BettaMan2000

    BettaMan2000 Fish Fanatic

    Joined:
    Oct 9, 2017
    Messages:
    154
    Likes Received:
    4
    What’s the max I could go for alongside either a pair of honey gouramis or blue/Bolivian rams?

    I don’t want a massive ammonia Spike that kills all my fish, I’m thinking of getting an extra 7, making twelve in total.

    Also what size of cardinal tetra should I go for, my LFS has small ones and larger ones over an inch?
     
    #12 BettaMan2000, Nov 16, 2017
    Last edited: Nov 16, 2017
  13. Byron

    Byron Member

    Joined:
    Feb 25, 2009
    Messages:
    5,947
    Likes Received:
    793
    Location:
    CA
    Last question first...I tend to acquire the younger (smaller) fish. For one thing, they are less expensive, for another they will live that much longer in your tank (or should). They might also settle in better. We are talking juvenile as smaller, not fry; it is true that fry have much less adaptability because they are developing so much so rapidly but that is not the case here with juveniles.

    Twelve cardinals will fill your 54 liter (15 gallon). I would not add Honey Gourami, and most certainly not rams, the latter need more space. Some small substrate fish like cories, one of the "dwarf" species would be better.
     
  14. BettaMan2000

    BettaMan2000 Fish Fanatic

    Joined:
    Oct 9, 2017
    Messages:
    154
    Likes Received:
    4
    My tank is a 24 inch wide so could be ok for honey gourami, but I’ve seen horror with these before!

    Is there anything brightly coloured and sizeable like three inch as a secondary fish I can get in there that isn’t going to hassle my tetras, I don’t just want one kind of fish in there.

    I Don’t know what kind of Corys exist?
     
  15. Byron

    Byron Member

    Joined:
    Feb 25, 2009
    Messages:
    5,947
    Likes Received:
    793
    Location:
    CA
    I would never put a 3-inch fish in this small a tank, except as an emergency (quarantine or treatment). Small tanks need small fish, not just visually, but the fish will be in better conditions because you can provide closer to what the species requires.

    I had a male Bolivian Ram and he grew to 3.5 inches. I had him in a 5-foot tank, my Amazonian riverscape as it then was; not suggesting a 3-inch fish needs five feet, but I have a fish room with 8 tanks--a 20-inch 10g, 24-inch 20g, two 30-inch 29g, two 36-inch (33g and 40g) and my two 4-foot tanks (sold the 5-foot, was getting old). He was quiet and sedate, never swam above a slow gentle cruise, and with a normal lifespan of 4-5 years he was well into his 9th year when he died last year. I would never have subjected him to anything below a 36-inch.

    There are more than 160 described species of Corydoras and many more discovered and assumed to be distinct species though not yet described. Most will be wild caught so attention has to be given to water parameters. Frankly, with all the threads I post in, I can't remember the parameters here. But very soft, soft, and moderately hard will be OK for several if not many or all species, depending. The three "dwarf" species are Corydoras pygmaeus, C. habrosus and C. hastatus; the first is common, the second frequent, the third rare. But with softish water and sand, a group of 9-12 would be OK with cardinals.
    http://www.seriouslyfish.com/species/corydoras-pygmaeus/
    http://www.seriouslyfish.com/species/corydoras-habrosus/
    http://www.seriouslyfish.com/species/corydoras-hastatus/
     
    #15 Byron, Nov 16, 2017
    Last edited: Nov 16, 2017

Share This Page