[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
It sounds like an Ostracod to me. Ostracods are small crustaceans that
swim about using their antennae, and chew on algae or other plant or animal
matter. They have a clam-like bivalve "shell" that encloses their body,
and fish do not relish eating them very much, although most aquarium fish
will whittle the population down to low levels in a few weeks. The
little, roundish ones, only about 1-2 millimeters long are pretty harmless,
although I have seen them get very numerous on rare occasions and actually
kill snails by harassing them to death.
There is a bigger, more oval species, about 3-4 mm long, that does damage
my plants severely when numerous, and it is very hard to eliminate. It
lays eggs that have variable hatching times, some delaying for over a year.
The small, roundish yellow eggs are stuck in crevices, and held in there
with some glue-like material. When I first got an infestation of these
larger ones, they spread to many of my plants in various tanks and jars
before I noticed the damage they were doing and got concerned.
I thought I could get rid of them on a plant by placing a piece of the
plant in water in a jar, and changing the water completely every few days,
thus washing out all the ostracods that hatched before they had a chance to
grow up and lay more eggs. I watched the jar closely, and wherever I saw
any little baby ostracods, I changed the water and rinsed off the plant.
Since the plant was floating in a bare jar, there was no substrate for the
ostracods to hide in, and I was sure that I got all the baby ostracods out
each time I rinsed. However, the plant continued to produce babies
seemingly indefinitely. It was still producing babies six months later,
when I finally gave up the experiment.
I have managed to free some plants of them, but it is a long process,
involving keeping the plants in a guppy tank for two to three years. I
have some C. parva that I think is now free, having been in a guppy tank
for 2 years, during which time it has grown from a single plant to a little
patch of about 10 plants. It hasn't had the best growing conditions, what
with numerous green water outbreaks alternating with periods of heavy
shading when I let the other plants become dense enough to make the green
water go away.
Paul Krombholz, in cool, dry, central Mississippi.