Cichlid Room Companion

Internet lectures

Husbandry of aggressive Cichlids

By , 1996. printer
Juan Miguel Artigas Azas, 2010

Classification: Captive maintenance.

" Fishroom talk taking place on 1996-Jan-31 "

Juanmi says: Well, Lets start, I won't use the PA system unless it is needed.

Joie asks: you said the topic was husbandry of large aggressive Cichlids? How large? how aggressive?.

Juanmi says: I would like to talk tonight on the first meeting to take place in 1996 about some ideas and tips about the husbandry of large aggressive Cichlids.

Juanmi says: Features like tank size, cover, mates, target fish, dither fish and food come over and over again in questions regarding the keeping of aggressive Cichlids.

Juanmi says: We have all seen the systematic and deadly attack from one larger Cichlid to others smaller in our tanks, beyond any reasonable cause.

Juanmi says: We keep asking how can we stop that seamlessly illogical aggression.

Juanmi says: We should in the first place know one important fact:

Juanmi says: That is that Cichlids in their natural habitats will rarely show that kind of aggression that we witness in our tanks, in fact, observing fish in the wild (and in some setups) we would never think they are capable of such deadly aggression.

Juanmi says: They will look so peaceful that no one would believe they could be real killers.

Horus says: kinda like charles manson.

Juanmi laughs.

Juanmi says: A second important fact to keep in mind is that there is not a straight procedure to avoid aggression, there is not such thing as a recipe against aggression that works in all cases, not even a recipe that worked once is guarantee to work again.

Juanmi says: Keeping Cichlids living in peace together is more like an art than a technical matter, it depends in great part of the sensibility, criteria and experience of the aquarist.

Juanmi says: One big mistake is to think that if we provide a very large tank aggression in our Cichlids will be gone.

Juanmi says: We could observe one Cichlid chasing another in a huge aquarium until manages to kill it, something could go beyond our understanding.

Juanmi says: On the other hand, we could observe rather small setups of aggressive Cichlids living in peace, something like we think is a peace of cake to keep those fish in harmony.

Juanmi says: Some considerations that should be keep in mind are as follows:

Juanmi says: Tanks size, yes it is important, but not an isolated factor or a guarantee that will be enough to keep our fish in peace.

Juanmi says: I would of course advice the larger tank you can get. That would be 150 liters (40 gal) for small African lake Cichlids or South American Geophagine species.

Juanmi says: For larger species of the same geographic areas a 375 liters (100 gals) tanks will be the one you need as your large tank.

Juanmi says: For Central American species, the large tank you have must be 800 liters (200 gals) or more. Central American Cichlids require larger tanks than most Cichlids from other geographical areas.

Juanmi says: You should also have in mind that wild fish (if you get those) for some reason are much more prone to show deadly aggression than tank raised ones.

Juanmi says: Second factor are the species you keep together.

Juanmi says: You must look forward to keep species that are not direct competitors (On feeding specialization), or that look very much the same. Those will tend to quarrel a lot.

Juanmi says: Species that are different or not competitors, that is, live in a different parts of the water column, feed on different meals will generally just ignore each other. Outside breeding time that is.

Juanmi says: It doesn't matter in this regard if they are different sizes, If there is no competition, they can't swallow each other, they will must likely just ignore each other.

Juanmi says: A third important factor is the density of fish in the aquarium.

Juanmi says: Fish in sparsely populated tanks will tend to show more aggression toward mates than those kept in more densely populated aquariums, that is the principle of the target fish method, which helps to disperse aggression over several potential targets.

Juanmi says: Of course, there is a limit in the density you can put in one tank to make it a suitable habitat for your fish.

Juanmi says: A fourth important factor, the environment:.

Juanmi says: Cover is always good, but keep in mind, not enough for a fish to escape aggressor punishment. On the other hand, one fish in a tank with plenty of cover could escape a deadly end hiding all his life. But then, what kind of life is that, he wont grow or behave normally, and most likely, will be prone to disease and never breed.

Juanmi says: So, cover is good but should be used in combination to the rest of the factors, not strictly necessary in all cases. Many people is very successful keeping Cichlids in bare tanks, so they can't hold a territory. But also, that won't allow them to behave normally though.

Juanmi says: Temperature and food are also important, higher the temperature, higher the aggression. Fish not feed regularly, tend to behave more aggressively towards tank mates.

Melissa says: And of course breeding may throw a wrench into an otherwise peaceful tank.

Juanmi says: Breeding seasons (As Melissa pointed out) could be a factor that changes the orders, boundaries and extension of territories, potentially causing a problem. Not just because the more aggressive breeding fish, but also because of aggressive Cichlids that get their territories invaded and relocated them.

Melissa says: I know my urophthalmus is a sweetheart (for her species) until she gets ready to lay eggs.

Juanmi says: If you see a Cichlid being harassed by another, take immediate action. Don't think things will settle down alone, 9 times out of 10 you will later regret.

Juanmi exclaims: An aquarium is an ever changing interaction, so a tank than keeps a peaceful habitat for some time, maybe years, may give you surprises. keep a constant eye on it!.

Juanmi says: In a tank with many Cichlids with all their scales and beautiful fins, not subject to general aggression, you may one day unexpectedly find a torn off fish, destroyed by the rest after for some reason he lost his territory.

Juanmi says: Try to get use to watch your fish communities, you will learn from them and that will help you to take preventive steps.

Juanmi says: If you cant have a balance with an aggressive Cichlid, take my word, use the incomplete divider method. Put an egg crate or glass divider (In this last case let one inch open at the lower part) in the middle of the tank, your fish will be more secure this way.

Juanmi says: You can make a hole in the divider where just the female fits so she will learn to go in and out the male's territory, the risk is diminished considerably this way, not gone though, a male can kill her with just one unlucky stroke.

Juanmi says: If you want to avoid any risk or the pair are the same size, make no holes, eggs laid will be still fertilized in the most part If they are placed close to the divider.

Juanmi says: But above all this, what counts the most is the sensibility of the aquarist. How he balances the factors before mentioned and the environment, to manage to create a suitable habitat for his/her fish. There is not, as I said, a given recipe that always works to keep aggression down in all cases.

Juanmi says: Remember that just your common sense and knowledge of the Cichlid species you keep will prevent deadly fights, even so, you will have to fate disgraces, you will learn from them.

Juanmi asks: Any questions?.

Kidd says: the best Cichlid is the angel!!! (:.

Juanmi says: Well, thanks you very much for your attention, I promise I will edit the log file into a readable and logical transcript (will have to work hard on it :)).

Joie says: juanmi, I have a 135gallon, how many oscars, once they are full grown, might get along comfortably?.

Juanmi says: 135, I would say four to six adults, Oscars are not very aggressive Cichlids as their fame may indicate.

Juanmi says: When smaller, keep more of them, you could then cull them to get your favorites as they grow.

Joie says: I'm not sure about them not being aggressive...I had 2, added one and then another, fishes 1,2,and 4 bullied #3 literally to death.

Juanmi says: Perhaps you should keep more fish, don't forget that fish in the tank already have territories, those that come in doesn't have one, they are in big risk.

Juanmi says: That reminds me, Introducing mew Cichlids into a established set up is a risky business.

Joie says: I moved the rocks and plants around, as I've read and heard to do, to 'confuse' them. it didn't seem to help in this particular case.

Juanmi says: That is not always a good idea Joie. Once you move all around, fish that already had a territory will loose it in the reorganization, getting prone to be targets of aggressions.

Joie asks: What I have now are two juvenile Oscars, about 2-3 months old, in a 20 gallon long. should I get more of this size and put them all in the 135 at one time?.

Juanmi asks: That depends, are they doing fine together?.

Joie says: yes - they follow each other around like puppies. it's cute. You hardly ever see one without the other.

Juanmi says: then you wont need to change anything by now, they may go like that forever, one thing is sure. You will need to move them to a larger, lets say 270 liters (70 gals) tank when they grow more, the 135 gals will do just great when they grow larger.

Joie asks: so I shouldn't introduce more Oscars?.

Juanmi says: You don't need to, unless you want to, but then again, introducing more fish could be a risk, better leave it as it is now if you are satisfied with what you have.

Joie asks: When it's time to move them to the 135, what other fishes might work out well with them?.

Juanmi says: You move them whenever you want, just don't wait too much, the small tank size could be a risk of aggression, also harder to keep in good shape. About the mates, medium sized catfish (Not fish eating catfish) will do, Heros severus will do just great, Pike Cichlids will also do it. Large Aequidens are also a choice.

Joie asks: would a callicthys cat (armored) of about 8", for instance, be ok?.

Juanmi says: That catfish will do just great.

Joie asks: what is an aequidens?.

Juanmi says: I mean a fish of the genus Aequidens (although many had been sent to different genus), like bujurquina, laetacara, etc.

Joie asks: I'm not familiar with those. where do they come from (besides the fish store)?. Juanmi says: They come from South America, they are restricted there.

Joie says: juanmi, thank you for the help. talk to you soon...

Juanmi says: Well, have to go myself, good night all, and thanks again


Artigas Azas, Juan Miguel. (May 27, 1996). "Husbandry of aggressive Cichlids". Cichlid Room Companion. Retrieved on October 20, 2019, from: