THE MARINE AQUARIUM. Ill 



organized and, therefore, the most delicate creatures. From 

 this circumstance they require real sea water or artificial 

 sea water that has been some time in use, although I have 

 found that minnows may be introduced about a week after 

 the tank has been in vigorous operation and, if they are 

 so introduced, the other fish can be the sooner admitted, as 

 they seem, in some way, to prepare the water for the more 

 delicate creatures. I have also observed that many of the 

 anemones may be placed in artificial water that has been 

 iu use ouly a day, and that they will very soon open in it. 

 There arc some species, however, that will not bear the 

 artificial water, until it has been in use at least a week. 

 The American species (Actinia marginata) is one of these. 



Mr. Humphreys, in his " Ocean Gardens," says : " A ma- 

 rine Aquarium may be rendered interesting without the 

 introduction of fish ; and as their presence requires that the 

 water should be, once each day, aerated by means of addi- 

 tional water, introduced by the syringe or by a drip, con- 

 tinuing for some time from another vessel," he considers 

 that they may be, with advantage, left out ; but I cannot 

 agree with him at all : a tank without fish, at the best, is 

 but a quiet flower garden ; for, what are the zoophytes but 

 the flowers of the Aquarium, while all within is still and 

 solemn ? but, let us introduce one or two fish, and all is a 

 display of life and activity ; and, as for changing the water, 

 a vessel iu which this is done is not an Aquarium. I 

 have always kept fish in my marine tank, and the water in 

 it has never required to be changed, unless when some ani- 

 mal has died in a corner or nook unseen and so fouled the 

 water. We derive amusement and instruction from the 



