14 Dead Tetra Neon in one day :o(

[Mr.Kal]

I've had a 65 litre tank for over a year, inhabited by 2 'tiger fish' (I'm sorry I don't know the proper name for them) about 5cm long.
With these were 14 tetra neon (each about 1.5 to 2.5 cm long)
There have been no problems - regular cleaning etc and all fish were looking healthy and happy for over a year.

One week ago I added 3 Ancistrus (about 2cm long, black with very small white spotting all over body) in an attempt to keep algae from building up in order to keep the tank looking better between cleanings.
The last week, feeding routine has been the same as always.

Today I return from work and find all neon and ancistrus dead (((((( - some of them had a whiteish mildew-looking covering on part or all over.

I've googled compatibility charts etc but find no direct advice that there was some issue.

What have I done wrong as this is very upsetting for me (

 

[twoodrough]

Wow. Sorry that happened. Hope you can figure it out.

 

[stevedocs]

Bad times


The white spots could of been ich that spread when you added the new fish?

 

[Rivercats]

Did you test your water for ammonia/nitrite/nitrates? Something could have caused an ammonia spike, which could have been fueled if one or two fish died and the ammonia started building causing more deaths and on it went over the course of the day. Or the bristlenose pleco's what you call ancistrus could have brought something into the tank, as in some type of illness. Neons can be delicate so it doesn't surprize me that they all went so fast. Also did you check your ph? Older tanks can often have sudden ph drops which can also kill fish. Changing 50% of your tank water weekly helps add new buffering minerals to your tank which help keep your ph stable. Then again if you have soft water that is low in minerals that would definitely allow ph to be low. What I guess I'm trying to say is there could be a ton of reasons as to what happened. The thing to do now is do a 50% WC, test your water for the above, and don't add any fish for awhile. Hope this helps alittle.

 

[pcdebb]

sounds like ich to me. I do know that neons are very sensitive to ph changes also.

 

[Rivercats]

Quote: One week ago I added 3 Ancistrus (about 2cm long, black with very small white spotting all over body)

The OP is discribing what the Ancistrus looks like, which it happens to be a bristlenose pleco. He's not saying all the fish have/had white spots on them so it wasn't ick.

 

[pcdebb]

Today I return from work and find all neon and ancistrus dead (((((( - some of them had a whiteish mildew-looking covering on part or all over.

This is what tells me it's possibly ich

 

[Borderlesscott]

Personally I think you overstocked the tank, levels can rise very quickly in a tank that size. 2 Tiger Fish, probably Tiger Barbs and that many Tetra is around overcrowding in a 65 litre and you would have to be very well filtered to cope with the waste produced. Adding the 3 Ancistrus probably pushed you over what the tank could hold as they produce a lot of waste, 3 for a 65 litre is way to many. They probably died from an ammonia spike, the whitish mildew appears on most dead fish after while.

 

[tamtam]

+1 to Borderless. The tank isn't even 20 gallons, 3 plecos is just way too much. They have such big bioloads.

What is your regular water change schedule and when was your last water change?

My guess would be an ammonia spike.

 

[pcdebb]

.......

 

[pcdebb]

My mistake. Misread the liters as gallons, huge difference, and I totally agree with an ammonia spike. Way too much

 

[Mr.Kal]

Thank you

I wish to thank you all for the comprehensive replies.
I will now be able to make sure this kind of horrible thing doesn't happen again.

Once again, thank you all.