Newbie tetra help

[FJB]

I agree with your assessment, Nerrad.
Whether the tank was originally cycled in the most conservative (prudent) manner initially is a non-issue now. It is cycled. You lost one fish in the interim, for unknown reasons, but that seems to be in the past.
Tetras are schooling fish, but they also establish hierarchies and individual fish play dominant and subservient roles. These are additionally affected by gender, age/size, etc., seasons, etc.
I believe that is what you are observing, and there isn't a whole lot you can do, except by providing physical objects (driftwood, plants) that break lines of sight and allow subdominant individuals to hide from constant bullying. You already have some of that but perhaps you may re-organize and add more, which often shuffles established hierarchies.
Your tank is small and you introduced too many fish - that is sure. Regardless, you need to do frequent water changes, I would say no less than 50% once a week, and not overfeed.
In time, you may consider changing that awful blue substratum (I know that is subjective) and using natural decorations. Another issue is that the grain size of your substratum is too large, allowing uneaten food and feces to accumulate, spoiling water quality. You need to vacuum with water changes.
Good luck!

 

[Nerrad]

I agree with your assessment, Nerrad.
Whether the tank was originally cycled in the most conservative (prudent) manner initially is a non-issue now. It is cycled. You lost one fish in the interim, for unknown reasons, but that seems to be in the past.
Tetras are schooling fish, but they also establish hierarchies and individual fish play dominant and subservient roles. These are additionally affected by gender, age/size, etc., seasons, etc.
I believe that is what you are observing, and there isn't a whole lot you can do, except by providing physical objects (driftwood, plants) that break lines of sight and allow subdominant individuals to hide from constant bullying. You already have some of that but perhaps you may re-organize and add more, which often shuffles established hierarchies.
Your tank is small and you introduced too many fish - that is sure. Regardless, you need to do frequent water changes, I would say no less than 50% once a week, and not overfeed.
In time, you may consider changing that awful blue substratum (I know that is subjective) and using natural decorations. Another issue is that the grain size of your substratum is too large, allowing uneaten food and feces to accumulate, spoiling water quality. You need to vacuum with water changes.
Good luck!

Hi FJB
Thank you for the constructive criticism and points noted. I agree I need to change the substrate I would rather go for a sand but how would I change it without completely emptying the tank. What substrate would you suggest? I believe the tetras like a dark substrate.
the plants you see are all real and so is the drift wood. I appreciate I have introduced many fish but yes to compensate I do 50% water change every weekend and vacuumed the gravel each time as you suggest

 

[the loach]

If the plants are real there is no issue they will have used the ammonia, since your pH is 6.8 almost all of that is ammonium which is far less dangerous.
Look for a substrate grain size of around 2mm. Tan colored is fine, white or artificial colors will cause the fishes colors to wash out.
I have had black neons and glowlight tetras together consecutively for over 30 years, and have never seen aggression lasting longer as a nip or chase of a second or two, even with lower numbers as you have. I don't know what is wrong with him, but I do know the only time you see a black neon near the surface is when its sick or dying. It is not normal for them to do that, just as to intimidate a whole school.

 

[Nerrad]

If the plants are real there is no issue they will have used the ammonia, since your pH is 6.8 almost all of that is ammonium which is far less dangerous.
Look for a substrate grain size of around 2mm. Tan colored is fine, white or artificial colors will cause the fishes colors to wash out.
I have had black neons and glowlight tetras together consecutively for over 30 years, and have never seen aggression lasting longer as a nip or chase of a second or two, even with lower numbers as you have. I don't know what is wrong with him, but I do know the only time you see a black neon near the surface is when its sick or dying. It is not normal for them to do that, just as to intimidate a whole school.

Hi,
He doesn’t stay too close to the surface maybe about 2 inch down, kind of top 3rd of the tank. Thanks for that advice re the substrate, I will be changing it for sure as I hate the blue.it is a quick chase but this one dominates the whole top area of the tank all the time causing the rest to lay low. I don’t think he is nipping the others but he is so fast it looks quite aggressive. I chose the black neons as I read in loads of places they would be good rank mates. The one I lost was gasping at the surface just before I lost him. This on is just guarding the area for some reason.

 

[the loach]

Yes that's what I mean 2" down from the surface is not normal, just as guarding an area. Occasional fin nipping is normal.

 

[Nerrad]

So I have been watching him All day and he is still doing the same thing. He must be making the other fish’s life a misery if any of them go to the half way mark in the tank this one chases them away. It’s not nice to watch to be fair. Unfortunately I dint have anywhere to move him yet as I’m still setting up my second tank. He swims around the top end of the tank like he owns the place and seems to stare a lot at the area where I put the food in.

it’s water change day tomorrow and I will move things around in the tank to see if that helps

 

[Nerrad]

So yesterday I too the bully out of the tank and placed him in a container for just over 1 hour,I then put him back.
Well so far I think it’s worked. He is swimming around as normal with th Ernest and is no longer guarding the top of the tank.
Think he needed the naughty step for a bit lol