MARINE AQUARIA 



125 



Sea Horses. Owing to the vastness of the field we cannot here go 

 into a detailed list of marine aquarium inhabitants, but we cannot pass 

 the subject without special mention of those quaint fishes, sea horses 

 {Hippocampus). Although appearing like some mythological animal in 

 miniature, they are true fish. They make a very striking appearance in 

 the aquarium, always attracting great attention. Their tails are prehen- 

 sile and are used much the same as a monkey's, fastening themselves to 

 twigs, bits of grass or any small object, ready to let go in a moment, 

 swim a short distance and fasten somewhere else or perchance socially 

 link tails with another. Their movements through the water might be 

 described as being very sedate. Locomotion is produced mainly by vibra- 

 tion of the dorsal fin, the body being tipped forward at a slight angle. 

 Although the movement through the water 

 is not rapid, it has the appearance of being 

 accomplished entirely without effort. The 

 breeding habits of the sea horse are also 

 most peculiar. The female develops an 

 intromittent organ as the breeding season 

 approaches, while the brood-pouch on the 

 belly of the male becomes thickened and 

 vascular. The fishes face,, each other, the 

 female advances, places one or more eggs in 

 the pouch of the male, retreats and repeats 

 until the spawning is finished. When the 

 eggs have hatched, the pouch splits slightly 

 and he works the young out of it by gently 

 rubbing against a firm surface. The young 

 are as perfectly formed as the parents. 



Sea horses feed upon small marine Crus- 

 tacea about equal in size to daphnia. Some 

 European aquarists claim to have gotten 

 them to eat dried shrimp, but, so far as we are able to learn, nobody in 

 America has been successful in this. Although dift'erent attempts 

 have been made to induce them to eat daphnia, it has seldom been 

 accomplished. The author was fortunate enough to persuade sea 

 horses to modify their ideas to that extent, the process taking much 

 patience. Daphnia can only live about 5 minutes in seawater, so at 

 first they all die while the sea horses are apparently thinking the 

 matter over. By repeated trials the smaller fishes finally started to 

 eat, and the larger ones took the hint from the smaller. Shrimp 

 will eat the dead daphnia, but if much is left over it should be 

 quickly siphoned out or otherwise removed. Sea horses can, no 



Fig. 119. Sea Horse 

 (Maximum size) 



