Nearly all the Sun-fishes are nest-builders, some forming arbors, as we have seen, others scooping out nests on sandy shoals, while one, the Spotted Sun-fish, is more democratic, affecting muddy streams, where, on the approach of cold weather, it makes a nest in the muddy bottom, and there it lies dormant till the coming spring.
Who has not made friends with the Dace--_Rhinichthys atronasus_? He is a veritable finny jester. We have watched him in his watery retreat, and, perhaps unseen, have played the spy upon his domestic proceedings.
Life is a gala time to these little fishes. They have seemingly never a care or a bother. In jest they join in the chase of some curious minnow that intrudes upon their presence, suddenly changing their course to dash at some resplendent dragon-fly that hovers over the leafy canopy of their home, and as quickly darting off again to attack some bit of floating leaf or imaginary insect.
All is not play, however, even among the Dace. The warm days of June usher in the sterner duties, the nesting-time. Male and female join in the preparation, and a locality, perhaps in shallow water in some running brook, is selected. Roots, snags and leaves are carried away, both fishes sometimes found tugging away at a single piece, taking it down-stream, and working faithfully and vigorously until, in a few hours, a clearing over two feet in diameter is the result.
There the first eggs are laid. The male, who has retired, soon appears from up-stream, bearing in his mouth a pebble, which is placed in the centre of the clearing. Now they both swim away, but soon returning, each bearing a pebble, that is also dropped upon the eggs. Slowly the work proceeds, until a layer of clean pebbles apparently covers the eggs. A second layer of eggs is now deposited by the female, and these are covered by pebbles as the others had been, the industrious little workers scouring the neighborhood for them, seemingly piling up eggs and stones alternately until the heap attains a height of eight inches or more. These heaps vary in shape, some being pyramidal, and others dome-shaped.
Such patience as these finny housekeepers manifest is not appreciated by man. The gleaners of the golden fields, in whose waters our little friends are found, have not discovered their secret, and think the curious piles the washes of the brook itself. But their purpose is the protection of their eggs. In swift-running streams, which these fish are so wont to affect, the eggs would be washed away, and, driven against rocks and snags, would be destroyed, or, even escaping destruction, would, by the undulating movement to which they would become subjected, be rendered impossible of incubation. Besides, were they not thus protected, even though there was no danger of being washed away, they would become easy prey to the attacks of carnivorous fishes.