302 



THE YOUNG 



NATURALIST. 



bottom and after a wriggle or two they die. 

 Enquiry on your part brings the knowledge 

 that your glass is too crowded, that the fish, 

 having consumed all the oxygen in the water, 

 are dying for want of air. So you set to 

 work to give the survivors fresh water ; and 

 this has to be done every other day or so, 

 which entails a large amount of labour, to 

 say nothing of sundry messes and slops, 

 resulting in black looks from Betty, who is 

 not of a naturalistic turn of mind, and who 

 can't be always wasting her time with 

 cleaning up master's fid-fads after him. 

 And, after all, the result is not quite satis- 

 factory, for the water, however oft you 

 change it, never looks bright and clear as 

 you many times see it in an old pond with 

 muddy sides and clayey bottom. Further 

 enquiry lets in a v^hole flood of light, and 

 now you begin to see your way to success. 

 Water plants are necessary for the perfect 

 health and well-being of your pets. By a 

 wonderful law of nature all plants consume 

 carbonic gas and give off oxygen, whilst, as 

 is needless to say, all animals consume 

 oxygen and give off carbonic gas, so that 

 each supplies the other's wants: that, to- 

 gether with another little matter to be men- 

 tioned presently, is the main secret of a 

 successful aquarium. But beware how you 

 stock your glass : there are water plants and 

 water plants. Not every plant that grows 

 and flourishes in the water is fit to be intro- 

 duced in an aquarium. Some wont live at 

 all — they cannot bear the confinement, — 

 others run up tall and spindly and then die. 

 Some live and grow, but they have a knack 

 of getting themselves covered with a rusty- 

 coloured scum which is very unsightly, 

 whilst there are about half-a-dozen species 

 which really do well, they are a great orna- 

 ment, they keep the water bright and clear, 

 and there is no need to change the water 

 from one year's end to another. And this 

 holds good equally of small as of large 

 glasses. Instance.— I have a cylindrical 



glass 7^ in. high, 4^ in. across, holds pint ; 

 put in two small minnows, two handfuls of 

 weed, neither gravel nor sand; water un- 

 chanded for more than a year, and is now 

 brighter than when put in ; fish have been 

 perfectly healthy from first. 



Now you think you are on the right track 

 at last, but if you omit one other point there 

 is trouble in store for you yet. You say 

 there's nothing so inspiring as sunshine. 

 Everybody likes sunshine. I've a nice south 

 window with a good broad sill — that's the 

 spot for my aquarium. Put it there and 

 you will at once undo all your previous 

 good arrangements. If the water does not 

 get so hot as to kill the fish, it will in a 

 couple of days or so grow so thick and turbid 

 as to suggest the idea that some practical 

 joker must have been trying to fatten your 

 fish on pea soup. The cause of this state of 

 affairs is not very apparent at first, but it 

 arises from the fact that the water coniains 

 an infinite multitude of the seeds of micro- 

 scopic plants. Warmth and intense light 

 are favourable to the growth of these, and 

 they do grow till they sometimes make the 

 water so thick that you cannot see half-way 

 through it. Perhaps you ask how it is that 

 a pond, exposed to constant sunlight, does 

 not become equally turbid. The reply is 

 that the sides of a pond are not transparent, 

 and the sides of your glass are so, that the 

 conditions are vastly different. Fortunately 

 the remedy is simple. Remove your glass 

 to a north window, and in a few days the 

 water, no matter how cloudy, will clear 

 itself. Keep it in a north aspect, or, at 

 least, away from direct sunlight, and you 

 will not have to complain of muddy water 

 again. So far from being an abstruse pro- 

 blem, an aquarium is the easiest thing in 

 the world to keep in good order. Have 

 plenty of suitable plants — you cannot very 

 well have too many ; — don't overstock with, 

 or put together, unsuitable animals ; choose 

 I a northern aspect ; and — let them alone. 



