How to Handle Aggressive Fish Species in Your Aquarium

You don’t have to be a seasoned aquarist to accept that not all fish will get along. Aquatic species, whether they come from freshwater or saltwater habitats, are guided by certain behaviors that can make them aggressive. Such behaviors may be inherent or a result of events and conditions within enclosed ecosystems such as fish tanks. Fish will fight over food, territory, reproductive mates, or because it’s in their nature to fight for survival.

In community aquariums, different species are expected to coexist peacefully. These are the tanks nearly all aquarists strive to keep because of their colorful diversity, but physical aggression can even break out in these habitats. Here’s how to manage such behaviors.

When Fish Fight

As long as your fish are being provided with the right mix and quantity of food—one the most essential fish tank supplies, they won’t fight for nourishment. They may compete for live feed if they’re carnivorous, but this cannot be accurately described as a fight. Fighting over mates may be more common, but this kind of aggression mostly has to do with asserting dominance, which means the fighting will be short-lived and shouldn’t be expected to result in death. Territorial fights are more violent, and they’re more likely to occur against the same species. Naturally aggressive fish like Betta splendens are programmed to be solitary pertaining to species and will almost always fight another male.

Signs of Aggressive Behavior

You may see more posturing than fighting because you’re not constantly looking at the aquarium. Fish do pay attention to humans and won’t fight when you’re around because they’re distracted. You need to look for posturing in addition to signs of injury such as torn-off scales, scraggly fins, and scrapes, particularly around the mouth of fish that appear to be victimized. Smaller species are unlikely to start fights, but if they act too timidly around others, this could be a sign aggression is taking place in the tank.

When You Should Let Fish Fight

Competitive feeding is nothing to worry about, and the same goes for fighting for mates. Should you become aware of these situations, you shouldn’t intervene unless you can ascertain serious injury will occur. It’s always best to feed two different parts of the aquarium to enable less-aggressive fish to feed. Territorial aggression is another matter because fish should respect boundaries. For example, if you see an Oscar commanding a corner and another Oscar trying to take it over, the fight could turn ugly and would need to be stopped.

Separating Aggressive Fish

Rearranging rocks, plants, and decorations can be effective in terms of stopping territorial fights. If a territorial species is being aggressive toward other species, separation is required, but not necessarily a relocation. Check with your aquarium shop for breeder nets or “cages” that can hold a fish in an aquatic jail for a few days. This is often helpful in calming aggressors down.

Whether you’ve chosen fish species that are known to be aggressive or those that are generally more docile, it’s important to care for your tank properly to ensure your fish remain healthy for many years to come. Aquatic Warehouse has everything you need, whether it’s an aquarium dosing pump, filtration, nutritious fish food, or any other important supply. Stope by our store in Kearny Mesa, order what you need on our website, or give us a call today at 858-467-9297 if you have any questions.