distended abdomen and doesn’t seem to
represent, in my opinion, the balloon-body morphology, but rather a pathology
resulting from that mutation.
A balloon-bodied fish’s compressed
organs are subject to severe bloating and
blockages. While they can sometimes be
treated, the condition almost always leads
to an untimely death. You can try feeding
the fish frozen peas: simply thaw them,
remove the skin, mash them, and give them
to the fish. Peas work as a fish laxative, so
they help to relieve bloating.
More Molly Mayhem
One of my mollies is twirling
around in the aquarium like it
cannot control its swimming.
Any ideas why it’s doing this? Only one out
of my 10 mollies is acting like this.
It seems like we have a theme
going with this month’s questions
so far. Fish that have lost control
as you describe have suffered some
sort of severe neurological damage. One of three
“usual suspects” is probably responsible for
The first possibility is that it’s a problem
with your water quality, likely high levels of
ammonia. This may only affect a single fish,
even though multiple fish may be in the same
water. A fish that’s behaving erratically may
be displaying signs of stress associated with
To see if your fish is suffering from a water
quality problem, test your water and ensure that
ammonia, nitrite, and nitrate are at appropriate
levels (zero for the first two, and under 80 to
100 mg/L for nitrate). If the water quality is
poor, you should immediately do a 50-percent
water change, followed by a 25-percent water
change every other day for a week.
Before doing this, ensure that your tap water
is not to blame; this time of year, many water
companies add chloramine to the water supply,
which can be a direct source of ammonia. A
water conditioner that removes both chlorine
and chloramine can eliminate this factor when
using replacement tap water.
Secondly, it is possible that the fish is suffering
from some sort of chemical poisoning. Again,
this may affect only a single fish—perhaps he’s
more sensitive to, or just got a stronger dose of,
some sort of substance that made its way into
the tank. This can be something as seemingly
innocuous as a scented candle being lit too close
to the tank, or a cleaner sprayed on the front
glass, or paint fumes, or insecticide, or any
number of things. Fresh activated carbon will
help to pull this out, but by now it has likely
already run its course through the system.
Lastly, there are a handful of internal
parasites that can cause this, but they are
fairly rare. If your water quality checks
out and there’s no sign of any chemical
getting into the tank, your fish may have
fallen victim to one of these nasty bugs. One
possible parasite that could be the culprit
is Myxobolus cerebralis, which can cause
what’s known as “whirling disease” in
farmed salmon and trout, as well as wild fish
populations. This parasite has been found in
cichlids and tetras, and though I’m not aware
of it infecting mollies, I see no reason it
cannot. There is no reliable treatment for M.
cerebralis, so affected fish should be removed
I have nine marbled
angelfish in a 29-gallon
(110-liter) aquarium. I
spawned and raised all of
them myself. I am very proud of my
angelfish and I wouldn’t want anything
to happen to them, but I’m in fear now of
losing them, because they are all stressed
and hiding in one corner of the aquarium.
I first noticed their behavior after I gave
them a 60-percent water change, when I
took out all of their old tank decorations
and replaced them with new ones. The
angelfish seem to be afraid of the new
décor, so they hide in a corner away from
the new items in their tank.
Their water is clear and clean. I added
some water treatment to help them keep
their slime coating and reduce stress, but
I don’t notice any changes yet. They have
yet to show any symptoms—no white
spots, fin clamp, or any other indications
of disease other than hiding in the corner.
I spawned and raised the fish myself
and wouldn’t be against buying them
a new 55-gallon (208-liter) tank if you
recommend it. What should I do?
Corydoras catfish should be provided sinking foods to avoid the buoyancy problems that
may develop from air swallowed while feeding at the water surface.
Feeding peas to balloon-body mollies can
help relieve the intestinal blockages from
which they often suffer.