42 A Brief History of a River Tank. 



success may, perhaps, surprise some of our non-successful 

 aquarians. For instance, the water has never once, during a 

 period of over seven years, been pea-soupy, or even cloudy, or 

 otherwise than as brilliant as all that we have in our mind's 

 eye when talking of the " crystal spring" and the beverage 

 of Castally. There have been deaths in it — deaths by com- 

 pulsion, the result solely of experiments made with a view to 

 test the extreme capabilities of the system ; but there are in 

 the tank at this time gold fishes that I have had in my keeping, 

 and that have never been otherwise than healthy and happy, 

 during a period of more than nine years. If any of our 

 readers have kept gold fishes in glass vessels .as long or longer 

 than I have, I should much like to hear of it, and with the 

 fact a word as to the conditions. Furthermore, to keep this tank 

 in order is a matter of such small trouble that it may be literally 

 said to take care of itself. Ordinary dusting and occasional 

 cleansing of the exterior are, of course, necessary, and for the in- 

 terior there are two operations only that are needful. The fishes 

 are fed with rice boiled in water, or with bread crumbs. I believe 

 that bread is as good a food as they can have, and as it is 

 always handy, it is a great advantage to be able thus simply to 

 perform a duty which is generally too much neglected, for there 

 are still to be found some benighted people who think that gold 

 fishes can live on the invisible tenants of the tank, and get fat, 

 as it were, upon nothing. The other operation is the occasional 

 cleansing of the front plate inside. This is accomplished by 

 means of a piece of sponge, attached, by means of twine, to 

 the end of a stick, and the stick is thrust behind the tank, so 

 as to be always handy for the purpose. * This cleansing of the 

 front plate is performed about once a fortnight during summer, 

 and not more than once in three months during winter ; in 

 fact, it might be left undone from November to March, and the 

 view would be unimpaired by even the slightest film of con- 

 fervas ; but from March to October the growth is sufficiently 

 rapid to produce a perceptible green tinge on' the glass in 

 eight or ten days, and this is easily removed by the sponge. 

 In cases of long neglect I find the most effectual mode of 

 cleansing to be with a cloth on which a little silver sand is 

 sprinkled; this, drawn over the glass with the sand, brings 

 away the crust at once, and if carefully done, appears not to 

 cause any serious scratching of the glass, though if the glass 

 were of poor quality, perhaps it might. 



The reader has of course taken note of the omission from 

 this history of all mention of the introduction of plants to the 

 tank. I have never introduced a plant of any kind, yet the 

 rocky wall is richly coloured with microscopic forms of vegeta- 

 tion in beautiful green, bronze, and russet patches, and if the 



