lifechooser

Setup -
60 litre with back attached filter, airstone, light and sandy base.
About 5 each of Neons, Mountain Minnows, and amber tetras
Established a little over a year ago, with no deaths over the last 3-4 months.
pH - 7.5 as usual, ammonia & nitrita - 0, nitrate - 5 PPM

Last week I did a big clean out. About half of the ornaments came out, including the large crashed plane, and they got a scrub in hot water - no soap, just water. I left the rest of the ornaments in to try to keep some bacteria.

2 days ago I came home to find my wife had quarantined a minnow by putting it a ziplock bag floating in the tank. All of its scales had puffed up, and it had been nipped by other fish. A few hours later it died.

Then, strangely my tank light bulb went too.

We decided it looked fungally, so on the way home from work I bought some anti fungal/finrot medicine (and a bulb) in case it would spread. I followed the instructions, disolved 11ml in warm water, added it to the tank and removed the filter medium.

This morning my wife woke me early to tell me the fish were all dying. 3 fish were floating on the top of the tank (all minnows), and most of the others were missing.

My panic involved testing the water, putting the filter medium back in, and then changing 1/3rd of the water. Also I'd like to claim the record for fastest fishtank bulb change ever.

Right now I can see a tank full of happy fish. I can't see any fungalness, and the even the floating 'dead' fish are swimming around as though they were just having a light nappette. One neon did die though.

What why and how, and what should I do next?

Shawnie

im sorry for your losses meds and fish dont mix well usually....I think it was a combo of the meds(more instant) and removing the beneficial bacteria..although the latter, wouldnt have happened so fast so keep an eye on water parimeters for the next week or so... meds will probably kill the bacteria as it is filtering it out of your tank....at this point I would just stick to partial water changes everyday and use some stress coat+ to sooth the fish...for future sick baby's, you can purchase a small filter/heater and run it on your established tank at all times and when a fish baby is sick, move it to a big container(very cheap at some local stores) as a quarantine tank....good luck!

ladylouroll

did you also use a new sponge when cleaning, otherwise the sponge may have had some cleaning products left in it?

lifechooser

I'm hopeful that the bacteria is ok, as the bacterial part of the filter wasn't touched. Also, I was careful to use a new cleaning cloth.

The fish seem fine now, so I imagine it must've been a bad reaction to the meds. I think I'll throw that bottle out. Tomorrow, I'll change the filter again to ensure the meds are removed thoroughly, and do another 30% water change.

peacemaker92

Hi Life, so sorry about your losses. That's terrible. Glad it's working out fine now. About cleaning your filter, be careful not to disturb the bacteria, it could cause more trouble. I'd agree with Shawnie too. Be sure to do daily water changes to be on the safe side. Good luck!