I just found some eggs in my
tank. Could they be from my
Corydoras cats? I’m guessing
they will be eaten soon—is there any way
of protecting them?
Charlwood, United Kingdom
The genus Corydoras includes
approximately 200 species, and the
“cory cats” also include several non-
Corydoras species that are closely
related, such as Scleromystax spp. Many of these
fish are common aquarium fishes, including the
ubiquitous C. aeneus. These fish often spawn in
aquaria, particularly after water changes, and
especially if you’re using water that’s a bit colder
than the tank water.
When spawning, they will lay their eggs on
vertical surfaces, including the aquarium glass.
It’s hard to say if those are Corydoras eggs
without knowing what other species are in the
tank. But assuming they are indeed cory eggs,
while the eggs or any subsequent fry are apt to
get eaten by other fish, it isn’t unusual for a few
to make it. If you wish to attempt breeding your
cories, which I highly recommend, you really
have two choices.
First, you can set up a small breeding tank,
such as a 10-gallon (38-liter) aquarium with a
seasoned sponge filter. Relocate your cories there,
feed them well for a few weeks, and then do a
50-percent water change with water about 10°F
( 4°C) cooler than the tank water. If they spawn,
return the parents to the main tank. The eggs will
hatch in a few days, and they can be raised on
any number of fry foods, such as vinegar eels,
microworms, or even finely ground flakes.
Alternatively, you can simply remove any
potential predatory fish from the main tank,
and then let the cory cats do their thing. Many
smaller-mouthed fish will never bother the
eggs or fry.
Can guppies be kept in the
same tank as platies?
Guppies (Poecilia reticulata)
and platies (Xiphophorus spp.)
are both common aquarium
livebearers, and they are among
the most popular of aquarium fishes. Both
fishes prefer moderately hard, alkaline
water, though they are quite forgiving of
water conditions. While male guppies can be
somewhat aggressive both with each other and
with other male livebearers, the damage is
generally limited to an occasional nipped fin.
These species should coexist quite well.
The most popular platy seen in the hobby is
likely a hybrid species artificially created by
crossing the original platy, X. maculatus, the
swordtail (X. hellerii), and the variatus (X.
variatus). The guppy, despite its incredible
diversity, is a single species, P. reticulata. These
two fishes are not in danger of crossbreeding,
although the platy would cross with other
types of platies, as well as the variatus and
swordtails, which all share a common genus.
Send your questions about the
freshwater side of the aquarium
hobby to “Q&A,” T.F.H. Publications,
P.O. Box 427, Neptune, NJ 07754,
or submit via email to editor@tfh.
com. For answers to more time-sensitive questions, opinions on your
setup, or just to converse with like-minded members of the aquarium
community, please visit the TFH
Forum at forums.tfhmagazine.com.