Expert: Walter Hintz - 4/18/2010

Question
QUESTION: Hi! For my 8th grade science project my topic is aggression in Betta fish. I'll be showing the Betta's different object for about a minute (mirror, colored block, photograph) to see what triggers and aggressive response. Then I will see if they become more aggressive if there is food present, or a female present, or a hideaway cave. What triggers most aggressive responses? What causes most aggression (food, female, territory, other)?

Thanks so much!
-Sarah

ANSWER: Bettas usually become most aggressive when another male is present. In fact they think a mirror image is another male.
Are you doing an experiment with live Betta using a scientific? If so you will have to design an experiment and a way to measure the aggression.

---------- FOLLOW-UP ----------

QUESTION: I see.
Yes, I'm going to use a live male Betta. I plan on showing the betta the mirror and recording how it responds giving it a 2 for full aggressive response, 1 for half response, and 0 for no response. I'll let him look at the mirror for about a minute and then take the mirror away. I'll wait a minute until it cool down and show it a colored block. I'll record his reaction again and continue showing him different objects. By the end of that part of the experiment I should have figured out what sets him off (color, size, shape, etc). T

Then for part two I will have the mirror, a male betta, and a female betta. I will see if the aggressive response inflates with a female present. I will let the betta cool down, then show it the mirror again... this time with no female present, but with food present. I will wait a minute then show it the mirror with not food or a female present, but with a secret hide-away cave, therefor asking "What inflates betta's aggressive responses most? Food, females, territory, or other?" What do you expect I will find? What inflates most animals (water and land) aggressive behaviors?

What do you think of this experiment? Do you have any predictions, any suggestions? What inflates most animals aggressive responses?

Thanks so much!
-Sarah

Answer
Hi Sarah
 I thing your experimental design is very good. I understand that at one point you are planning to put the male and female together. Unless he is ready to mate he will attack her and possibly kill her. In nature she can keep away but in an aquarium you will have to have a place for her to hide or a way to keep them apart. I bred Bettas years go and I separated the tank with a piece of glass down the middle. My suggestion is to place her in a container and hold the container to the side of the tank where he can see her.  Here is another problem when using a female. The flaring fins indicating aggressive behavior are also used during the mating display so it is difficult to tell whether the male is being aggressive or showing his mating colors.
 You haven't stated your hypothesis yet. The hypothesis is a statement or prediction about the answer to the problem is. I cannot make any predictions for you. Aggressive animal behavior can be triggered by any of the things you are considering. Studies with rats have shown that thirst is the strongest drive. This would not apply to a fish. In most mammals hunger would be next and then the sex drive. I suspect that the fighting fish involves aggression toward a possible rival for the female. This is what the fish sees in the mirror
 Keep me informed Sarah