60 THE GOLDFISH AND ITS CULTURE. 
of newspaper over the water to which the scum will adhere. 
Once a week the sediment that has collected between 
the pebbles, introduced for this purpose, should be removed 
by the aid of a glass dip-tube or a rubber syphon. Sand 
that has been displaced by the fish, laying the root of the 
plants bare, is returned to its proper place with the dredge. 
This is a little scoop-like instrument of metal, fastened at 
right angles to a long handle. 
Sometimes it happens that a plant is pulled out of the 
sand by the fish, or accidentally by a visitor; such a plant 
should be re-planted without delay. Make a hole in the 
sand with the dredge, and use the diptube to hold it 
down at the roots while these are being covered with peb- 
bles and sand. 
Especially useful are these aquarium tools during the 
winter months, when the water is chilly, as they make it 
unnecessary to put the hands in the water at all. (See 
illustrations) p 141. 
RE-ARRANGING THE AQUARIUM. 
When the aquarium is to be thoroughly cleaned and re- 
arranged, which should be done once or twice every year, 
the water is drawn off with a rubber syphon to within about 
six inches from the bottom. (This water, if practicable, is 
saved and used again when the tank is re-filled, the older 
the water the better; water improves by age.) Next take 
out the rockwork, then all the plants, also the larger peb- 
bles, and now carefully catch and remove the fish, etc., 
placing them in a clean tin vessel with plenty of water of 
suitable temperature. Take out the balance of the water now 
and also the sand, but do not move the tank from its 
