Tank cleansing - HELP!

[MatthewShaw]

Posted in Emergencies, - please read

Tank: 36" x 12" x 12"
Containing: 11 Neon Tetras, 1 Catfish, 5 Platys, 3 Angels and 3 Clown Loaches.
Water tests: ok
I started my aquarium after xmas and gradually built it up to house the above fish. About three weeks ago I noticed what I suspected as Finrot on a Platy. (Ragged fins) Gradually other fish came down with the condition, some developing ulcerations around the fin area. I treated the tank with finrot and fungus treatment, but within a week all my fish are dead.
Some fishes had ragged fins and ulcerations, some had no visible faults whatsoever. I've maintained weekly water tests which have been very acceptable for amonia - 0 nitrates, nitrit, ph, high range ph and general hardness. All tests have been ehat they should be.
Does this sound like new tank syndrome?
I first intorduced the Tetras, followed by Platys Catfish and Loaches, which were followed a fortnight later by the Angels (and the first feed of live food!) it all went down hill a couple of weeks after this.

How do I start again? - Do I need to disinfect/boil up the gravel/tank? if so what's the procedure?
Can I keep my plants? - the only thing alive!!!

 

[QHowes]

Well it sounds like you have or had a serious problem. As to what it was that killed your fish i cant really give you much insight on that. But I can help you with your new setup. Personaly I would get rid of the plants and sterilize anything you plan on using in contact in or out of the tank, In the tank would be fake plants, decorations, etc. Outside of the tank i would sterilize your net and alga scrubber,etc. Use new gravel. Make sure to clean it thouroughly. Oh and dont forget that sterilizing includes your pump, which will need replacement charcoal filter and sponge inserts. Of course you will also need to cycle your tank. For cycling instructions see the pinned article in the begginer section. Good luck

 

[Bol]

If you are certain that you had zero ammonia, and zero nitrites, then there was probably something else in the water that irritated the fish.

This may be a silly question, but I didn't see any mention of it. Did you dechlorinate your water, both initially and during water changes?

As far as starting over, cleaning everything is a good idea. Might want to be careful if you decide to boil your gravel, and it's obviously colored (i.e. dyed or painted).

I find it hard to believe that there's a "killing agent" attached to your plants, but if you want to keep them, you may find it helpful to dip them in a solution of 1 part bleach and 19 parts water, for 30 seconds to 2 minutes each, depending on the frailty of the plant.

And, just for long-term info, a fully grown angel will probably feel cramped in a tank that's only 12" high (its top and bottom fins may get deformed, becuase there's not enough "room").