Antibiotics for your Aquarium Fish

PL wrote,

I read your article on SBD (swim bladder disorder) and I would like to know which anti-bacteria meds would be best.

A: I’m afraid it’s the usual answer, “it depends”. Different antibiotics treat different bacteria. Some treat gram-negative and some treat gram-positive bacterial infections. Beyond that, some are better for internal infections and others for open wounds or external infections. Since we virtually never have the means to test our fish, selecting the best antibiotic is often done using a combination of common sense and luck.

Obviously, if you suspect a bacterial infection that is affecting the swim bladder, you want something that will treat the infection internally. If your fish is still eating, a medicated fish food is usually the best option. Jungle makes Anti-Bacteria Medicated Fish Food that you can find easily online and in some fish stores. There are others out there too but medicated fish foods can be hard to find. It seems just when a good one pops up and catches on, the manufacturers discontinue it.

Another option is to treat the water itself. Since most infections are gram-negative I usually start with an appropriate antibiotic like Mardel’s Maracyn-Two or Maracyn-TC which you can now buy in powder form. Often what I will do is dissolve the pill in a small concentration of tank water and soak the food pellets in it for a few minutes. I pour the medicine mixture in the tank following any directions for filter removal, and give the soaked pellet to the fish. This is less than scientific but it is always my goal to get the medicine into the fish. Another good broad spectrum antibiotic is Triple-Sulfa. It’s a good all around medication treating internally and externally.

Some medications treat both gram-positive and gram-negative bacteria. This is also an option for you to consider. On one hand it may seem like over-medicating but when you don’t know what is wrong with your fish, it can be a viable option. Mardel’s Maracyn and Maracyn-Two can be used in conjunction and are easily found at most local fish stores and large pet supply retailers.