When it comes to keeping fish, wrong and right are easy to differentiate: if it’s right they survive, if it’s wrong they die. Within the ‘right’ there is still the possibility of better and worse. In a better tank the fish thrive, in a worse tank they survive.

Survive: The fish is provided its basic needs to survive: water, oxygen, and food.

Thrive: The fish is provided with an environment as natural as possible within the aquarists’ means to achieve the best possible health and the most natural behaviour.

The mixed tank of aggressive New World cichlids easy to recognize because it contains one of this, one of that, a couple of this or that… and the owner is often eager to find a new fish to add to the mix. Sometimes the mix is simply two different species, other times it’s an abundance of them, This type of tank can classify as right:worse – it can work, but it’s not ideal.

Why it works: These tanks are usually overcrowded with species that may or may not be of similar size and temperament, and the tank is usually sparsely decorated. This environment makes it difficult for any particular fish to establish a territory, and aggression tends to be distributed amongst several fish, making it seem less. The fish tolerate each other, a sort of forced truce.

Why it doesn’t work: The mixed tank will often backfire on newer fish keepers. Cichlids are programmed to see other species as threats and competition, not as friends and companions. It is far from uncommon for a fish keeper to come home one day to a dead or dying fish, easily recognized as the victim of assault from the physical damage incurred. The owner may wonder what went wrong. Everything was working and he had not made any changes in the tank.

There were changes, but it was the fish themselves that changed. They grew from tolerant juveniles into territorial adults. The adult aggression has surfaced along with the first victim. As the fish mature, fights will often start over territory, battles will be waged over females (even of different species), and bullies will often show their true colors, often for no apparent reason. The once peaceful community has sunk into civil war.

Sometimes it doesn’t happen so brutally or quickly. It may appear to work, but a new fish keeper may not notice the signs of stress from the weaker or more timid fish in the tank. In these cases it’s only a matter of time before the fish succumbs to disease, due to a lowered immune system (a direct result of constant stress).

Why it isn’t recommended: We know that this setup can work and we know it can fail. Perhaps it worked thanks to careful planning, or maybe it was sheer luck. A bit of both? Either way, there are reasons why this setup is less then ideal, and why, despite how common these New World tanks are, they are worth avoiding.

We return to the idea of surviving versus thriving. If cichlids see each other as enemies then mixing them is going against their nature, whether we can make it work or not. When we go against their nature, it has a direct impact on how naturally they are able to behave and how well they thrive in the long term. Their behaviour is what comprises the charming character that makes these fish so endearing to keep.

Not everyone cares about behaviour. The goal of some fish keepers is simply to keep many different species for a colourful and diverse tank. There is nothing wrong with this. There are, however, better cichlids to suit the purpose. Malawi cichlids, for example, thrive in mixed communities, and their vivid colors and active nature make them perfect for these types of aquariums. Having never kept new world cichlids before, or having only kept them in a mixed tank, it’s understandable that the keeper may question what I mean by natural behaviour.

New World Cichlids are high level fish. They respond very well to their mates, often communicating through physical displays and subtle body language. Many species are monogamous, developing solid relationships with a single partner that can often make human relationships look fragile. Polygamous breeders are a little more complex, given the relationship between the male and the females as well as between the females. Colony breeders are even more so, with relationships between the males, the females, and the males and females. Keeping cichlids with their own kind promotes the kind of behaviour we’d observe in the in the wild, because they are living in similar conditions. When it comes to New World cichlids, less is more.

Spawning may not be the first priority of the aquarist, but keeping the fish in these breeding groups offers the natural behaviour that brings the most out of the fish. Other then the never ending search for food, breeding is the only thing they try to accomplish during their simple lives – without it we’ve lost the largest and best aspect of their behaviour. As another by-product of this type of tank, many courting cichlids will show a display of color very rarely exhibited in a mixed tank.

Aquarists have different minds about what the aquarium is about, yet it can only be hoped that all these aquarists have one same common goal: To provide the best home possible (within their means) for their livestock. The important part about keeping fish is not to keep them in any specific way, but to find types that are most suitable to the aquarists’ preference.

One persons perspective. Cheers

This post has been edited by freddyk: Sep 21 2005, 03:07 AM