Neon Tetra Misbehaving

[Ashz]

So I have just started a 95 Litre / 20 Gallon Tropical Aquarium.... and it was fish ready so I purchased 1 male Betta and 5 neons as the lady recommended as a start (because I want 1 Betta no matter what..) On the first night I noticed 1 of the neons was missing an eye, checked back later and discovered it was missing both eyes and floating on the surface... I assumed it was the Betta and separated him.

Two night on and I have discovered that one of the neons is in perfect shape, whilst the other 3 remaining neons seem to be damaged with parts of their fins missing etc... I assume now that this neon killed the first neon and has been damaging the other neons because I watched it for a while and it chases/bites at the other neons...

What should I do?

 

[merry78]

do you know about cycling and the required stats for ammonia, nitrite, and nitrate?
if your tank was not fully cycled (this involves feeding an empty tank with measured amounts of ammonia for several weeks to build up a population of nitrifying bacteria, not just running the tank empty for a week as most fish shops recommend), your neons may be suffering from finrot, stress and poor water conditions that could result in the fin damage you describe. Your betta may have picked on them too, as you said, however an uncycled tank will be your biggest problem at this stage.
have a read of this:click me
and this: click me too
and then this part for a general info overview: click me for general info

you will see that a lot of this info is different to what a fish shop owner will tell you, but this info aims to keep your fish healthy long-term, not make money from you like a fish shop.

if your tank is correctly cycled, and you know all of the above info, perhaps finrot or bullying is your only problem. If it is bullying, adding more neons will help, but adding more neons in any other scenario will only make things worse, so make sure you read the links before you decide!!

hope this helps, and welcome to the forum!!

edited for spelling

 

[Ashz]

Thank you very much for your help and all of the information, I was able to learn a lot.

I will update later on with the results