How harsh/dangerous are antibiotic treatments (Furan / Maracyn)

[Spar]

In general, how harsh or dangerous to a fish are antibiotic treatments? Like with the products Furan-2 or Maracyn Plus. If you were just paranoid about a situation with a fish and decided to dose one of these products 'just in case', would that be a bad idea? (would be in a QT/HT, obviously)

Mainly looking for the likelihood that the fish could perish merely because of the medication.

 

[Deinonych]

I haven't used Furan-2, but I've used Maracyn Plus and Kanaplex several times. Both are very gentle - fish don't even notice you are medicating.

 

[HumbleFish]

Fish don't usually die from antibiotics themselves (unless you OD), but rather they succumb to a quick killing gram negative infection and the antibiotics get the blame. That being said; IME erythromycin & minocycline (i.e. Maracyn 1 & 2) are "gentle" with regards to side effects, but can be slow acting and too little too late when dealing with an aggressive infection. Furan-2, on the other hand, seems to clear infections faster, but I have also witnessed more appetite suppression with it.

IMO it's more important to determine what type of infection the fish may have and treat accordingly. Gram positives, most often seen in established fish, can easily be cleared with erythromycin in most cases. Gram negatives, more likely encountered with newly purchased fish, require aggressive antibiotic treatment and even then, most fish still succumb. So again, I think fish dying suddenly from gram negative bacterial infections (usually within 24-48 hrs) is why the antibiotics that got dumped in just last night gets the blame.

 

[MrTuskfish]

Treating people or fish with antibiotics as a preventative measure is never a good idea.