My Baby Neons are Dying

[Nathrakh]

Over the last day 4 out of 10 of my neons have died, and the other don't look to well. I have a 140 litre tank that's been running for five week now (I added the neons three weeks ago and all seemed well until this weekend). They have two other tankmates; a red whiptail catfish and a Golden pleco (both of which are fine). Just wondering whether any of you had any ideas what I could have done wrong.

 

[Nathrakh]

Sorry, I've just realised I've posted this in the wrong forum. I repost it in the beginner's questions.

 

[Eelzor]

We're all here to learn!

 

[Inchworm]

Hi Nathrakh and welcome to the forum