WATERS AND HOLDING PROCEDURES
Q
tion between members of the same genus appears to
occur.
Both the number produced and survival of guppies
has been shown to be controlled by an inhibitor.
We might now make some generahties on aquarium
management that take into consideration the foregoing information. New water should be used for
flushing aquaria and for making aged and conditioned water. Aged water is ideal as an environment
for young fishes of aU species. In the culture of many
fishes aged water for fingerlings is considered a necessity. For small species of fishes that utilize the tiny
plants and animals contained in aged water, aged
water would be of value for flushing tanks.
Conditioned water is a matter of concern in growth
studies. In this type study the initial filling of the
aquaria should be with conditioned water. It is possible that only a part of the water need be conditioned, i.e., a tank might be fiUed with new or aged
water and then a portion of conditioned water added.
The primary concern with polluted water is the
development of aquarium management procedures
that avoid the accumulation of putrescible materials.
As pointed out above, food and fecal material are
normally the principal source of trouble. Fecal material should be removed by periodically siphoning
off the bottom of the aquaria. Trouble from food is
avoided by not overfeeding and by the selection of a
food that is not too rapidly soluble in water. Some
foods, as for example, ground Hver, are very troublesome to feed, while Hve foods such as water fleas
(Daphnia) and brine shrimp (Artemia) seldom produce a pollution problem. Ammonia and other gases