View Full Version : Gentamycin question

Scuba Guy
01-20-2007, 02:37 PM
Has anyone used Gentamycin?

Back in November, I broke the rules and introduced some angels to my established tank without quarantining them. Sure enough, my angels started dying within days ... everyone of them. I was horrified. I could tell it was some sort of bacterial infection since the fins were quickly rotting away on all of my fish, fins were clamping, fish were listless and stopped eating. All within 48 hours.

I didn't want to treat the whole tank believing water changes and increasing temps would take care of it.....wrong. With a bacterial infection, the last thing you want to do is increase the temperature. It just speeds up the infection.

I bought more angels from a reliable shop in town to start over (grow juveniles into breeders) and sure enough, they started to show the same symptoms....this time I had to act fast.

I put Gentamycin in the entire tank according to the dosage level.

This stuff is a miracle drug. Within hours, my fish started to recover, first the fins unclamped, breathing became less labored and most important, they started to attack their food again. The fin rot after several months is now almost healed - especially on veils.

My question is : are there any lingering affects of the Gentamycin. I have done many water changes since then, so the residual Gentamycin must be near zero....but my tank has this milky hazy look to it. It is not crystal clear like it used to be. Use of a diatom filter helps, but only for a short while (the haze comes back within hours).

My thinking is that the Gentamycin wiped out the natural bacteria in the tank and that I may be having a bloom as the tank repopulates (w/ good bacteria?). The bio filter seems fine since all of my chemical readings are zero (including Nitrate because of the plants), NH3/NO2, etc.

Is this normal? I would think after a few months, the tank would return to normal - but maybe it takes longer....

blue fin
01-20-2007, 02:48 PM
did you put your carbon filter in to get the meds out? the meds may have stayed in the substrate keeping the cycle from coming back...I would say it is quite possible that this is a bacterial bloom... check your ammonia, nitrtite and nitrate to confirm where your cycle is.

Scuba Guy
01-20-2007, 03:02 PM
I did run a separate carbon filter for 24 hours - the water changes I am sure removed about 90% of the water with new water - and each water change I do continues to reduce the old water (w/ residual meds).

I am told that Gentamycin is stable for about 7-14 days in tank water and then breaks down.

How long should it take for the bacterial bloom (which isn't bad, just ugly) or whitish haze to last? Am I talking months here?

also - my Ammonia, Nitrate and Nitrite are all zero. I'm sure the plants help with that regardless of the bio-filter.

Lady Hobbs
01-20-2007, 03:52 PM
Sorry about the death of your angelfish. I currently have 9 angels and they are my favorite fish.

It does sound to me as some of your biological media was destroyed with the use of this medication. Parasite meds won't do this but fungal meds will. It won't take too long to establish itself again but in the meantime, you will once again experience ammonia spikes so please pay close attention to your water and do your testing daily. You may have to do daily water changes if you get ammonia spikes as angels can't take anything but very clean water.

I would also use medicated food now for a week or so to make sure all signs of this bacteria is gone from them. It's rather like us humans stopping antibiotics too soon and an infection re-occuring. Medicated food may get rid of any remaining bacteria they harbor.......if any is remaining.

I wish you well in the angels recovery process and getting that tank clear again.

01-21-2007, 09:34 AM
Do you have a name of a medicated fish food? I can't seem to find any specific names or brands online... Maybe my Google skills are rusty.

01-23-2007, 01:12 AM
is that the only teatment you've tried?