
AILMENTS AND DISEASES 

Batrachosperms are small gelatinous masses of Algze which attach them- 
selves to plants and submerged wood. 
Lemanea grow in masses and form a turf-like covering on stones in 
water often two inches long. Some of the forms of this genus are present 
in all freshwater. 
Nostocs ceruleum, N. depressum, N. sparicum and N. lobatus, are Alge 
which adhere to aquatic plants and form tiny dark-green, brown and 
blackish tufts. 
Cylindrospermum minutus, forms filamentous light-green to rusty-brown 
intricately felted minute masses on aquatic plants. 
Gloiotrichia incrustata, forms tiny clusters of light-green, straight and 
stiff filaments bearing round fronds the size of a mustard seed on water 
plants. 
Rivularia cartilagine, appear as sub-globose, stiff, deep brown or 
blackish threadlike filaments, having small semi-globose fronds or cells 
containing spores, and attach themselves to aquatic plants. 
Scytonema immersus, and S. negelii, form dark green mats on aquatic 
plants, and S. dubium, dark masses binding the leaves together. 
Other Algze which cause green water and scum on ponds and stagnant 
water are Oscillaria, Hydrodictyon, Zygnomacia, Wolfia and Vaucheria. 
Diatoms and Dismids are also often present in great numbers. These 
serve as food for fishes, and are in part the first food of the alevin and fry, 
their silicious casings aiding in the development of the bones. 
Conrerv#. The Cladophora are the larger members of this genus, 
two of which are common in Eastern waters. hese are C/. fracta and 
Cl. brachystelecha. Vhey seldom occur in aquaria, but Scenodesmus polymor- 
phus, develops in quiet pools and ditches in such numbers as to make 
the water clouded and very green. It consists of short and slender fila- 
ments with tiny threadlike branches. 
Aquarium fanciers have been led into considering all minute water 
plants as Conferve. They are a small group of the large family of Algae, 
and mostly of larger size than those which occur in aquaria. 
Stime Funcr. When the sides of breeding tanks do not become 
coated with alge, two or three species of the Myxogastres or Slime Fungi 
are likely to form. ‘These are injurious to the spawn and young fishes 
and should be removed. 
Pranr Func. A number of injurious fungi on the larger aquatic 
and semi-aquatic plants are likely to be encountered by the aquarist. The 
more general of these are:— 
Rhizopus necans, affecting lilies introduced from Japan. It lives as 
a saprophyte in the soil and becomes a wound parasite, gaining access 
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