FisJi Stiddy 171 



LESSON XLI 



The Stickleback 



Leading thought — The stickleback is the smallest of our common fish. 

 It lives in stagnant water. The father stickleback builds his pretty nest 

 of frog-spittle which he watches very carefully. 



Method — To find sticklebacks go to a pond of stagnant water which 

 does not dry up during the year. If it is partly shaded by bushes so much 

 the better. Take a dip net and dip deeply ; carefully examine all the little 

 fish in the net by putting them in a Mason jar of water so that you can see 

 what they are like. The stickleback is easily distinguished by the five 

 spines along its back. If you collect these fish as early as the first of May 

 and place several of them in the aquarium with plenty of the algae known 

 as frog-spittle and other water plants they may perhaps build a nest for 

 you. They may be fed upon bits of meat or liver chopped very fine or 

 upon earthworms cut into small sections. 



Observations — i. How did the stickleback get its name? How 

 many spines has it? AVhere are they situated? Are they always carried 

 erect? How are these spines used as weapons? How do they act as a 

 means of safety to the stickleback? 



2. Describe or make a sketch showing the shape and position of the 

 dorsal, the anal, the ventral and the pectoral fins. What is the shape of 

 the tail? What is the general shape of the fish? 



3. What is the color of the sticklebacks? Is the color always the 

 same? What is the color and position of the lateral line? 



4. Describe the eyes. Are they large or small? Can they be 

 moved? Do you think they can see far? 



5. Describe the mouth. Does it open upward, straight ahead or 

 downward ? 



6. When the stickleback is swimming what are the positions and 

 motions of the dorsal, anal, tail and pectoral fins? Can you see the 

 ventral pair? Are they extended when the fish is swimming? 



7. When resting among the pond weed of the aquarium what fins 

 does the stickleback use for keeping afloat? How are the other fins held? 

 What fins does it use to move backward? Which ones are used when it 

 lifts itself from the bottom to the top of the aquarium ? How are its fins 

 placed when it is at rest on the bottom? 



8. Drop a piece of earthworm or some liver or fresh meat cut finely 

 into the aquarium and describe the action of the sticklebacks as they eat 

 it. How large is a full-groum stickleback? 



9. In what kind of ponds do we find sticklebacks? Do 3^ou know 

 how the stickleback nest looks? Of what is it built? How is it sup- 

 ported? Is there one door or two? Does the father or mother stickle- 

 back build the nest? Are the young in the nest cared for? At what 

 time is the nest built? 



Supplementary reading — Fish-stories, Chap. XXXVI, Jordan and 

 Holder. 



