Page:The fairy tales of science.djvu/169

 green film that sometimes forms upon the glass. The star-fishes, crabs, serpulæ, and the prawns are favourites with aquarian naturalists; but the lovely sea-anemones are the crowning glories of the glass tank. We must carefully remove all dead plants and animals from our aquarium. It is indispensable that there should be a free access of light, but we must not expose our tank to the full glare of the sun's rays, or the water will become heated, and its delicate inhabitants will surely die. These tanks require constant attention, but their beauty will more than repay us for any amount of trouble. They have been beautifully described as "flower gardens which never wither, fairy lakes of perpetual calm, which no storm blackens."