Strange Swimming

It could be the ammonia, and  the water change should sort that out.

But keep an eye out for any of the following:
red stripe looking bleached
blue area glowing yellowish
bent spine
lumps on the abdomen which go to a point

These, together with swimming oddly, are signs of neon tetra disease. Fingers crossed it was just the ammonia.

just to update since doing a water change all the fish seem a bit more lively, although the ammonia was not really high at all it was according to my hagen kit just on the edge of safe so not overly a big concern. the one neon tetra i was concerned about seems to be missing an eye, could this be why he is swimming on the wonk?

It looks like a hole rather than old injury the fish is only 2 months old so I'm not sure whether it had its eye missing from birth or not, I thinking it's probably new as I would have noticed before it swimming funny without a doubt. No idea how it happened can't imagine any of my other fish attacking it they are all quite friendly.

Thanks for your help as usual. Will update if there are any other changes and hopefully it is a case of an injury rather than illness.

Provided that is the only symptom (in other words, provided it's not Neon Tetra Disease) the other fish should be OK.

If you think the fish is suffering, you might want to think about putting it down. We would do this with a dog that was in obvious pain with no cure.
Euthanasia