Territorial fish are best added to communities last of all. In fish aquariums where the tropical fish are all territorial, but some more aggressive than others, the least aggressive should be added first, the more aggressive species a few weeks later, and then the most aggressive a few weeks after them. This will give each batch of fish a chance to claim a territory.
Aggression problems within schools can be fixed by adding further specimens. In the case of tiger barbs for example, fin-nipping amongst themselves and toward other tropical fish in the freshwater aquarium are most common when they’re kept in groups smaller than 10. Sex ratios are important too, and among species like mollies where aggression between males is common, it’s important to have at least twice as many females than males. In extreme cases, if a schooling species isn’t kept in adequate numbers, the dominant fish ends up harassing or killing all its companions; piranhas are notorious for this, but it can happen with tropical fish such as and Chromis too.
My semi aggressive tropical fish tank
Ship wreck cove setup for small non aggressive tropical fish.
A mistake made by many inexperienced aquarium owners is to accidentally purchase aggressive tropical fish and add them into their beautiful family of fish. Suddenly the aquarium goes from being quiet and calming, to a snack bar and buffet.The freshwater Angelfish is a very popular tropical fish because of its unique shape and because of their interesting personalities. Freshwater angelfish are aggressive eaters and will go to the top of the tank when they see you approach. Because of their aggressive feeding habits, make sure that your less aggressive fish are getting their share around feeding time.Aggressive tropical fish do not always attempt to eat the other fish, but will always be the aggressor in the tank. They may bite off parts of fins, bump, or simply chase the other fish incessantly.Owning aggressive tropical fish can be great fun. Owning Piranha and watching them voraciously go after their food is enjoyed by many people. When you buy fish with the knowledge of what you are getting and how to handle them you will have great luck. It only becomes a problem when you ignore the signs and combine your aggressive fish with other fish they see as their lunch. Use common sense and keep your aggressive fish in a special tank, and enjoy watching them mix with their own species.Even the seemingly innocent Betta Fish needs to be treated with caution. You need to be careful to never put two males in one tank or you will learn the meaning of aggressive tropical fish in a moment. The two males will go to battle and not stop until one is floating on the surface.There are many species of Swordtails including the Lyretail swordtail, and the Green Swordtail. Also known as Swords, these live-bearing fish are a peaceful community fish. Swordtails are not the hardiest of tropical fish, they need good water quality but they are easy to care for if this condition is met. Be sure to do your proper water changes in your aquarium. Swordtails are a schooling fish, but they do not form tight schools. Regardless, they need to be with other Swordtails, mixing species together is fine. They can live on their own but are less stressed and more active when they are mixed with other live bearers, including other Swordtails and Platies. Swordtails can be kept with most freshwater fish but avoid overly aggressive fish.