Using Antibiotics
I'm certainly not going to recommend any antibiotics here, but
I would like to offer some general observations. The first set is
on modes of administering antibiotics. There are three principle
options, listed from most effective to least:
- Injection. Based on a diagnosis of the pathogen
and the fish's body mass, an appropriate selection and
amount of antibiotic can be injected.
- Ingestion. The antibiotics can be placed into
the food. Gel foods are particularly suitable, since the
medicine has less opportunity to leach out into the tank
water before being eaten. A dosage must be calculated
based on the amount fed and the fish's mass. Both Tetra
and Romet make premedicated pellets. The idea is that the
antibiotic is absorbed as it passes through the digestive
track.
- Immersion. The antibiotics are dissolved in the
tank water or in a bucket for a short term dip. This is
the most common and least effective method, since many
antibiotics are composed of molecules that are too large
to pass through the skin or gills. So they end up being
topical treatments. In some cases, this may be adequate,
particularly for secondary infections associated with
injury or stress.
If you have a situation where you are confident that an
antibiotic is appropriate and you plan to use method (3) above
with the antibiotic dissolved in the tank water, here are some
general suggestions:
- Don't mix a lot of different chemicals in the water.
Stress Guard has been reported to precipitate some
antibiotics out of solution, as an example. Salt should
be pretty safe, but it is very difficult to anticipate
the result of mixing medicines, water treatments, etc. If
you don't have a good diagnosis of the disease, and are
bound and determined to use an antibiotic, pick a broad
spectrum antibiotic (there are many over the counter ones
available in pet shops) and use it alone for the
recommended period, before trying anything else.
- I turn off my filter immediately before adding medicines
to the tank and usually leave it off for 6 to 12 hours.
This may not be a good idea for everyone; you'll have to
judge what is best for your setup. My goal is to try to
minimize the damage to my biofilter. Many medicines
decline markedly in potency in the first few hours they
are in the tank water. So my filter doesn't get exposed
to the full potency of the medication if I turn it off
during this initial period.
- If you lose a fish after treating it, put it in the
garbage or bury it. Don't put it down the toilet. There
are enough antibiotic-resistant bacterial strains in the
environment as it is, without introducing new one into
waste water.
