TKOPICAL AQUARIUM FISHES 95 



ture as that in the aquarium, which should be of an uniform summer 

 heat. Keep no other fish with CichHds. 



B6 GROUP 



THE GOBY GROUP (Gobiidie). These include bottom fish from 

 all over the world, occurring in shallow streams or shallow shore-waters — 

 marine, brackish and fresh. Little is known of their spawning habits, 

 beyond the fact that some spawn among — and on — the stones on the 

 bottom. Others — ^^small species — will spawn on the inside — /. e., concave 

 side — of a piece of drain pipe laid on its side in the aquarium and others 

 spawn among the weeds (roots) on the sand or mud. Some protect 

 their spawn. Others do so but little if at all. Among the Gobiidae are 

 our well-known "Darters" — familiar to the country schoolboy — also 

 the "Miller's Thumb," "Tommy Cod" or "Sculpin" (Cottus ictalops, 

 Rafinesque) and the most peculiar "Mud-Springer" (Periopthalmus 

 koelreuteri) from the Tropical Tide-waters of Africa and Asia. Shallow 

 water is a prime requisite for these fish, the last named species requiring 

 stones projecting above the water, sloping up gradually, upon which the 

 fish likes to climb out of water and "bask." As to rearing the young, 

 aquarists must experiment and persevere, as very few have had much 

 success with them and those who have reared any have been European 

 aquarists with abundant time and patience. 



B7 GROUP 



LABYRINTH FISH (possessed of an air-cavity or cell beneath 

 each gill-cover, in which a supply of air is stored for breathing). These 

 fish are all air-breathers, coming frequently to the surface to replenish the 

 air in the "storage chamber." Most of the Labyrinth fish build "bubble 

 nests", i. e., secrete a "glue" in their mouths, and blow air-bubbles 

 coated with this glue, which float in a mass and in which the male 

 places the eggs, immediately after fertilization, which takes place in 

 mid-water, the parent fish intertwining their bodies immediately under 

 the nest of bubbles at frequent intervals, extruding a few eggs at a time. 

 Then as the fish relax their embrace, the male catches the eggs in his 

 mouth and blows them — each one separately — into the air-bubble nest. 



As soon as all the eggs have been extruded from the female and 

 fertilized in the external embrace of the parent fish, the male having 

 gathered all eggs into the floating nest, he then drives the female to as 

 distant a comer of the aquarium as possible (as he knows that she will 

 eat the eggs if she gets a chance) and for about 36 hours the male fish 

 guards the nest and eggs and re-arranges the eggs and adds more bubbles 

 where required. Towards the end of the hatching process, the male 

 spreads the nest out as much as possible, to give the hatching young as 



