Sudden Loach Deaths

[sheree]

For the past 12 months I have had 4 zebra loaches. However, 3 of them have suddenly died this evening with no obvious causes. I've tested all water stats which shows ammonia = 0, nitrate = 20, nitrite - 0, ph 6.2 which is what it has been for the past few months. It has only affected the zebra's no one else seems to be showing any signs of any problems and they seem to be feeding ok. When I inspected the dead fish, there was no signs of trauma apart from on one there was a little mark on its back like it had bumped itself but nothing on the others. I'll be carrying out a water change shortly. Any suggestions?

 

[WILDER]

When you say bumped can you describe more in detail.
Did the loaches lose colour or go darker.
Were they acting lethagic and hiding away.
Were they rubbing themselves on tanks ornaments.
Just anything to go on.

 

[sheree]

I'd noticed in the past few days that they didn't swim backwards and forwards at the front of the tank like they usually do at night though they were still fairly active. The bump on his back seemed more of a small mark like he'd caught himself on an ornament or something. None of the loaches faded to grey. I have a clown loach and she is certainly the boss in the tank, could she have done something? though they have been fine together for so long which is just the odd thing about it. The other 2 seemed fine.

 

[WILDER]

Not sure whats gone off to be honest.
Not enough info to take you anywhere.
I would just do some water changes and see how it goes for now.
Make sure there no ornaments that are sharp in the tank.