86 



ZOOLOGICAL SOCIETY BULLETIX 



ter, a small net made of cheese-cloth held 

 over the aquarium with the left hand will of 

 course catch the solid matter as the water 

 falls back. The operation should be re- 

 peated until all waste is removed. It is well 

 occasionally to aid aeration by dipping up 

 some of the water, raising the dipper six or 

 eight inches above the surface, and pouring 

 it back. The stream of water will carry back 

 air. Avoid as much as possible the disturb- 

 ing of the plants. A fresh-water aquarium 

 does not require direct sunlight. 



For cleaning the inside of the glass use a 

 long-handled' pad of wood about 2^4 inches 

 long by i^ inches wide and three-eighths 

 of an inch thick, covered with two or three 

 thicknesses of soft woolen knit goods. If 

 the aciuarium is round, shape the sides of 

 the block to fit the curve of the glass. 

 All confervas (vegetable growth) is easily 

 removed by rubbing the glass, and if the pad 

 is washed often the water will not be soiled. 

 The growth of confervse on the rear side of 

 the aquarium need not be removed, as it is 

 a good aerator. If after several months, per- 

 haps a year or more, the plants have grown 

 to excess and the gravel has become some- 

 what foul, carefully remove the animal life 

 to some receptacle and siphon the water into 

 buckets. Soft rubber tubing is best for the 

 j)urpose. Take out the plants, wash the 

 gravel, and clean the inside of the glass. It 

 is well when returning the water to raise the 

 dipper, pouring it in as previously described, 

 for aiding aeration. Avoid resetting a fresh- 

 water aquarium as long as possible, as it dis- 

 turbs the rooted plants. If the water is clear 

 and the animal life appears healthy do not 

 touch it. A few suggestions should be made 

 as to the size and number of fishes, newts, 

 and tadpoles which can be maintained under 

 favorable conditions in a four or five gallon 

 balanced aquarium. Fishes from 1^2 to 2jX 

 inches long, three or four; newts, four or 

 five ; tadpoles, if they are not too large, three : 

 snails, six or eight. As the newts come to 

 the surface for air they will not therefore be 

 a detriment to their gill-breathing com- 

 panions. 



A salt-water aquarium is somewhat more 

 difficult to stock and keep in a healthy con- 

 dition than one of fresh-water, but is more 

 interesting, as there are more species of ma- 

 rine animals which can be procured and kept 

 in such an aquarium. The self-sustaining 

 aquarium is a wonderful field for the study 

 of the smaller marine forms. In many re- 

 spects the manipulation and care of salt-wa- 

 ter balanced aquaria are similar to those of 

 fresh-water. Use beach-gravel on the bot- 



tom about one inch in depth. A part of it 

 may be quite coarse, as small anemones will 

 attach to the pebbles, and the bottom is 

 easier to keep clean. It is well to place some 

 pieces of rock in the aquarium, which will 

 add to its beauty and make a home for anem- 

 ones. 



There are several formulas for making ar- 

 tificial sea-water, but it has never been used 

 at the New York Aquarium. The ocean is 

 the natural source of supply, and it would be 

 difficult to improve on nature. The practical 

 plant for the aeration of the sea-water aqua- 

 ria is the so-called sea lettuce ( Ulz'a latissiiiia), 

 which can be procured in tide-pools and shel- 

 tered coves near shore. Having the gravel 

 and pieces of rock bearing anemones placed 

 in the aquarium, carefully fill it with water, 

 so that you do not disturb the unattached 

 anemones if there are any. The Ulva grows 

 in very thin sheets, and is extremely tender 

 when young, therefore it requires careful 

 handling. Use small pieces of cork to float 

 it, allowing a portion to hang down near the 

 bottom on the rear side of the aquarium. 

 This arrangement forms a background, and 

 shows the anemones and other life to good 

 advantage. Cover about half the surface of 

 the water with the Ulz'a, leaving the front part 

 for light. Solicria is a good sea weed for the 

 bottom of the aquarium. Its color is a beauti- 

 ful red, and makes a handsome contrast to the 

 green Ulva. A species of coral can be secured 

 on the New Jersey coast at Long Branch and 

 vicinity and in Long Island Sound which will 

 live for years. Its tentacles expand freely, 

 and it is very interesting. Several species of 

 tropical coral can be kept alive for years in 

 balanced aquaria. 



Ovsters, clams, and mussels can be kept 

 with sea anemones and coral, but shrimp, 

 small hermit, horseshoe, and blue crabs had 

 best be by themselves, for they will rob the 

 sea anemones and coral of their food. Of 

 the annelida, or worm class, the Scrpida 

 ' live and thrive for years, and Sabella for many 

 months, also the tube-worm Cistciiidcs. The 

 sea-squirt lives well and multiplies, and one 

 or two species of Botryllus. Close scruti- 

 nizing of the aquarium will often reveal col- 

 onies of hydroids, which appear suddenly 

 and may live for several months. Sea anem- 

 ones are fed with the soft portions of a 

 clam or oyster. The coral will require it 

 chopped quite fine. Take a little at a time 

 on the end of a slender rod, tapered to a 

 point, and place it carefully in contact with 

 the tentacles, near the centre of the disk, 

 where the mouth is situated. Crabs and 

 shrimps will take it from the bottom. It is 



