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Betta Behavior and Husbandry: Linking Betta splendens Aggression with Community Tank Preservation

By Lonnie Lindberg

Bright colors, elegant finnage, and a feisty attitude to boot….these are the traits that have attracted young and old alike to the remarkable world of the Betta fish.

Known as the Siamese fighting fish, the domesticated betta (Betta splendens) began in the rice paddies of Thailand. There are over a dozen wild known betta fish species living in the world today, with most being found in southern Malaysia and nearby Indonesia. In these tropical waters, the wild betta fish is a far cry from the gorgeous domestic strain. They lack the vibrant colors and the gorgeous trademark fins. Domesticated male betta fish come in a variety of colors and fin types. There are twelve fin styles in all, but the most common types are the veil tail, crown tail, delta, super delta, and half moon. Females tend to be not as popular as the males due to the lack of the graceful fins. However, they too come in a collection of eye-catching colors that can rival any male.

What is common between the wild male betta and the male Betta splendens is that both are known to display extremely aggressive behavior between fellow males and unwilling females. I have also witnessed extreme aggression from female betta fish, as well. Therefore it is important to know and understand the factors that can trigger the fighting instincts in the Betta splendens, especially within the males of the species.

Researching Male Betta splendens Aggression
In college I conducted two experiments on male betta fish behavior. All test subjects were kept separate and no animals were harmed during the course of the experiment. All of the bettas were kept in 10 gallon (37.5 litre) tanks during both tests. As is necessary for bettas, the water temperature was kept between 79-80 degrees Fahrenheit (26-27 degrees Celsius). Just as with humans, they require a healthy and variable diet full of fiber. Since these are carnivorous fish, I provided a diet of brine shrimp and freeze dried bloodworms. Before feeding, I recommend gut loading the brine shrimp. Crush up some flake fish food and wait about half an hour for the shrimp to ingest the flakes. Daphnia, blood worms, and brine shrimp are an inexpensive and necessary component of your betta’s life. To avoid overfeeding, I recommend feeding betta fish once every three days.

Experiment 1
For my first experiment, I hypothesized that male Betta splendens only attack males of the same species. To avoid distraction, all the tanks were kept bare of any substrate or furnishings. I was quite surprised and somewhat thrilled of the final product. I’ll spare you the statistical results and simply say that my hypothesis was thoroughly mistaken. Not only were there attempted attacks on fellow males and females, but also on a male fancy guppy and a fish that looks nothing like a Betta…a goldfish. Yes, you read correctly, a goldfish. I honestly wasn’t that surprised about the attacks on the guppy as male fancy guppies tend to resemble the physical characteristics of bettas. Yet a goldfish that looks nothing like a betta and is larger in stature still provoked aggression.

Experiment 2

My second experiment was presented at the 28th Annual Western Pennsylvania Research Symposium at Carlow College, Pittsburgh USA. With this one I wanted to determine if territoriality was linked to a form of cover in the male Betta splendens. In this test I had six male Bettas as my subjects and provided aquatic plants as the form of shelter. I tested when two males had cover, when neither had cover, and when only one had cover. All fish were tested against each other in those scenarios for a total of sixty trials. I thought that having a form of cover would indeed provoke more aggression. No, once again I was proven incorrect. One would think that the males would fight over luscious plants perfect for egg laying. However, males were more aggressive without any cover at all.

What Does This Mean For Betta Community Tanks?

My research revealed that there can be multiple contributing factors in betta fish aggression. Therefore it is important to know and understand the dynamics that can trigger the fighting instincts in the Betta splendens, especially within the males of the species. One such factor is age. In my report I noted that my older males were more interested in foraging around on the gravel floor than in fighting. The average pet store betta is already quite mature upon arrival. Unless you’re buying from a betta breeder who knows the lineage and age of all of his stock, there’s no way of knowing the “personality”. The variety of betta also seems to play a role. For example, the Crown Tails seemed more willing to engage in combat and appeared to have a more energetic display than the Veil Tails. Naturally, genetics can also contribute to behavior; however I did not know the lineages of my test subjects.

When rearing Betta fish think about surroundings. In these tests, plants seemed to be used mainly as a place of refuge from rival males (maybe even from potential predators) rather than as a reproductive factor. Only if a female was present did a male even attempt to venture out. It’s quite possible that the energy needed for mating is too important to dissipate during combat. It could also be that females choose males on their nest options rather than physical prowess. Whatever the motive, offer plenty of hiding places with preference to thick aquatic plants. If you’re not a plant person, try aquarium safe décor with hidey holes or even make your own out of large rocks. Offering hiding places lets bullied fish have a place of sanctuary. This is especially important if you have a female betta in the tank. It gives her a place of solitude away from the physical stresses of courtship. Plus female bettas are also known to be very territorial, so use these habitation tips for her too. I don’t think it wise to have a male and a female betta sharing the same tank unless you are attempting to breed. In that case, study breeding techniques from reputable sources. Some of my references, Mr. Bob Fenner and Mr. John H. Tullock, are two of them. I also recommend adding a betta fish to your tank, male or female, last. That way it will be difficult for the fish to establish a territory. Furthermore, don’t worry about a male betta catching any of your other pets. Those fins are for display; not for speed. It’s also less likely females will be able to catch other fish if there are plenty of hiding places.

Now that shelters are readily available, it’s acceptable to add other species of fish to the betta tank. Only have peaceful community fish as tank mates and be sure they are not known for fin-nipping. The following table presents some of the suitable and unsuitable betta companions.



Female Bettas (with caution)

Male Bettas (any variety)

Neon Tetras


Cardinal Tetras




Rasboras (Harlequin, Scissortail, Red-Tail, Clown, and Pygmy)

Cichlids (Angelfish, Oscars, Discus, all species)

White Cloud Minnows


Glass Catfish

Shark Catfish

Coolie Loaches


Corydoras Catfish




African Pygmy Frog

African Clawed Frog

Gouramis have been known to get along well with betta fish, but it’s kind of a shot in the dark. Both fish can battle for dominance. If you want to attempt this try the following species. Remember that gouramis tend to grow rather large. Make sure you have enough tank space to occupy one. Have only one gourami per tank, please.


Blue Gourami

Pearl Gourami

Croaking Gourami

Dwarf Gourami

Keep in mind that the suitable afore mentioned fish are compatible for one very important reason: They all require similar water chemistry. Just like the betta, the appropriate mentioned fish thrive in tropical waters. So please don’t try pairing a betta fish with a cold water community fish. It just doesn’t work. With this in mind, you won’t have to worry about sacrificing one species for the other. Once more offer plenty of hiding places; preferably thick aquatic plants.

A Happy, Healthy Aquarium

My research in no way finalizes male Betta splendens behavior or the nature of their aggression. What it does reveal is that there are many contributing aspects to the violent conduct of the domesticated male betta. As such, be sure to take the necessary precautions when creating any aquatic environment. In the case of the betta fish, whether male or female, the Betta splendens will bring color and grace to any aquarium. Just be sure to provide a safe habitat for both betta and fellow tank mates. After all, a safe fish aquarium is a happy one.

Tankmates for Bettas. Betta Fish Junkies, 2008
Fenner, Bob. More Than Corys: The Armored Catfish of the Family Callichthyidae., 2008
Betta Tail Types: A Basic Guide. Tropical Fish Forum.Net, IPS, Inc. 2008
Betta Care. TFH Publications, New Jersey, 2002.
The Guide to Owning Bettas. TFH Publications, New Jersey, 2003
Tullock, H. John. Your Happy Healthy Pet: Betta 2nd Edition. Wiley Publishing, New Jersey, 2006.
Betta Compatibility 1, Betta Compatibility 2., 2008




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