Fish Schooling

Fish Schooling

Abstract

This experiment tested schooling behaviors between two species of fish. The fish used to conduct the experiment were Zebra Danio fish and minnows. The number of fish required for schooling and elapsed time was also accounted for. The results showed that mixed-species schooling may occur. The numerical quantity and time also proved to be a factor in the experimental results.

Introduction

A fish school is another word for a large unit of many fish which congregate amongst each other. Schooling is common practice among most fish, and there are many advantages toward schooling. One advantage is hydrodynamic efficiency; due to the hydrodynamic properties of water, fish have an advantage by swimming through water together (www.marine...). Schooling of fish is also used as an effective predator protection strategy. Schools are usually uniform in behavior and appearance, and predators may be drawn to disproportional schools (Ward, et al, 2004). Research also shows that fish in similar developmental stages tend to school together (Ward, et al, 2003).

Fish school for many different reasons. However, will fish school with species other than their own? Are the factors of time and number relevant when determining schools? In the experiment I will investigate these questions. My hypothesis is that three fish of one species must be added in order for schooling between the species to occur.

Materials and Methods

In order to test the hypothesis, four zebra and four minnows were collected. These species were approximately of the same length and width. One species of fish were placed in a large glass cylinder on the left-hand side of a 15 gallon aquarium. The aquarium was marked in half by a line drawn vertically down the middle of the glass. Each time a fish crossed over the line it was considered “schooling”. The other species of fish were kept in a bucket of water until needed. Using a fish net, one of the fish in the holding bucket was placed into the aquarium on the right hand side. The fish was timed for one minute. Next, another fish of the same species was added and timed for one minute. Finally, a third fish of the same species was added on the right side and timed for one minute. The behavior of the fish was observed during each one minute interval. The entire experimental process was replicated twice, and fish species in the aquarium and the bucket were switched.

Results

In the first trial of the experiment, the zebra fish added to the tank stayed on the right side of the tank for the entire one minute interval. After the second zebra fish was added, both stayed to the right for the entire interval. Finally when the third zebra fish was added all three exhibited schooling after 30 seconds had elapsed.