Fish as Nest-builders. 



them up to the surface. This process is repeated several 

 times, until the little fish has got together sufficient 

 threads to start weaving his raft. When he has woven 

 together a mass of threads about an inch in diameter, 

 he rises to the surface, takes in a large gulp of air, and, 

 without enclosing it in mucus after the manner of the 

 Paradise-fish, liberates it beneath the raft which he is in 

 process of weaving, and which is thus buoyed up. Off 

 he goes in search of more plant threads, and these as 

 they are collected are fastened alongside the first, until 

 the whole mass measures some four inches in diameter. 

 Once more he ceases from weaving, and pays a succes- 

 sion of visits to the surface to collect more air to liberate 

 it beneath the raft, until the middle begins to rise as 

 a tiny green rounded dome, some two inches above the 

 surface of the water. More confervae are now collected 

 and placed around the dome, and carefully and stoutly 

 woven into place, like a broad flat brim sewn on to 

 the crown of a dome-shaped hat. 



This remarkable raft-nest completed, the little Rain- 

 bow-fish escorts a series of females beneath it, so that 

 their floating eggs are placed beneath the shelter of the 

 dome. He then mounts guard and tends the eggs, in 

 very much the fashion of the Paradise-fish, for about 

 three days, and then, that the eggs may be completely 

 surrounded with water and the young successfully 

 hatched from them, he makes a hole in the top of the 

 nest and lets the imprisoned air escape, with the result 

 that the dome falls in, and both raft-nest and eggs sink 

 gently down to the bottom. As soon as the young 

 hatch out, the little Rainbow-fish proceeds to undo the 

 firmly woven edge of the nest, and ravels it out until 



63 



