preventive for vibriosis?

[marieK]

I just lost a 1 yr old tank- raised juvenile Premna biaculeatus that is in with 2 other same age batch of clowns. This was the smaller of the clowns but did not seem to be unduly picked upon by the other 2 fish. They are in a 20 gal tank with a couple pvc pipes. They are in a grow out, bare bottom tank with a filter sponge that they grew up in and the nitrates tend to be on the high side due to heavy feeding@2o. I am currenlty feeding formula1 flake twice a day and marine cuisine once daily- not a new regimen. Onset was fast - died within 12 hrs. Intial symptoms were erroded fins and listless, not eating well. Only med I had at home was formalite2(formaldehyde, copper and nickle sulfate). I did a 25% water change today after retrieving the dead body. No other external discolorations/ parasites seen on microscopic examination. The other 2 fish appear normal.
I suspect vibriosis since I did not see reddening at the base of fins as described in my reference books. Would you suggest a preventive treatment of antibiotics for the remaining 2 fish? I have access to amoxicillin, metronidazole and erythromycin tablets. Thanks for any input. -Marie

[billsreef]

Fin erosion and death in so fast a time frame would have me suspecting protozoan nasties as opposed to bacteria.

If in doubt, use both shotgun barrels and treat with copper (cupramine is best IMO) and a good antibiotic, preferably Nitrofuran, Maracyn 2, or Kanacyn.

Metrondiazole is primarily effective against deep tissue anaerobic flagellate infections. Erythromycin is not particularily effective at the high pH of a marine tank. Amoxicillin I have not used and am not familiar with it's effectivness at various pH's so cannot comment on whether or not it will be effective.